Consolidate the glob case logic

Looking at the code as a whole, we ended up with a little to much "buttons". It turns out that doing case insensitive matching (lower both pattern and strings to match) performs just fine. Or at least, it
gives the penalty to the people who uses mixed case filenames.

```
GetGlob/Default_cache-10                          10.6ns ± 2%    10.6ns ± 1%   ~     (p=0.657 n=4+4)
GetGlob/Filenames_cache,_lowercase_searchs-10     10.6ns ± 2%    10.6ns ± 0%   ~     (p=1.000 n=4+4)
GetGlob/Filenames_cache,_mixed_case_searchs-10    29.7ns ± 1%    29.6ns ± 1%   ~     (p=0.886 n=4+4)
GetGlob/GetGlob-10                                13.7ns ± 1%    13.7ns ± 0%   ~     (p=0.429 n=4+4)

name                                            old alloc/op   new alloc/op   delta
GetGlob/Default_cache-10                           0.00B          0.00B        ~     (all equal)
GetGlob/Filenames_cache,_lowercase_searchs-10      0.00B          0.00B        ~     (all equal)
GetGlob/Filenames_cache,_mixed_case_searchs-10     5.00B ± 0%     5.00B ± 0%   ~     (all equal)
GetGlob/GetGlob-10                                 0.00B          0.00B        ~     (all equal)

name                                            old allocs/op  new allocs/op  delta
GetGlob/Default_cache-10                            0.00           0.00        ~     (all equal)
GetGlob/Filenames_cache,_lowercase_searchs-10       0.00           0.00        ~     (all equal)
GetGlob/Filenames_cache,_mixed_case_searchs-10      1.00 ± 0%      1.00 ± 0%   ~     (all equal)
GetGlob/GetGlob-10
```

7 files changed, 25 insertions, 51 deletions

diff --git a/hugofs/glob.go b/hugofs/glob.go
index e691cdc10..1b649a283 100644
--- a/hugofs/glob.go
+++ b/hugofs/glob.go
@@ -26,19 +26,20 @@ import (
 // Glob walks the fs and passes all matches to the handle func.
 // The handle func can return true to signal a stop.
 func Glob(fs afero.Fs, pattern string, handle func(fi FileMetaInfo) (bool, error)) error {
-	pattern = glob.NormalizePathCaseSensitive(pattern)
+	pattern = glob.NormalizePathNoLower(pattern)
 	if pattern == "" {
 		return nil
 	}
+	root := glob.ResolveRootDir(pattern)
+	pattern = strings.ToLower(pattern)
 
-	g, err := glob.GetFilenamesGlob(pattern)
+	g, err := glob.GetGlob(pattern)
 	if err != nil {
 		return err
 	}
 
 	hasSuperAsterisk := strings.Contains(pattern, "**")
 	levels := strings.Count(pattern, "/")
-	root := glob.ResolveRootDir(pattern)
 
 	// Signals that we're done.
 	done := errors.New("done")
diff --git a/hugofs/glob/filename_filter.go b/hugofs/glob/filename_filter.go
index c4b582bd5..8e8af554b 100644
--- a/hugofs/glob/filename_filter.go
+++ b/hugofs/glob/filename_filter.go
@@ -49,7 +49,7 @@ func NewFilenameFilter(inclusions, exclusions []string) (*FilenameFilter, error)
 
 	for _, include := range inclusions {
 		include = normalizeFilenameGlobPattern(include)
-		g, err := filenamesGlobCache.GetGlob(include)
+		g, err := GetGlob(include)
 		if err != nil {
 			return nil, err
 		}
@@ -60,9 +60,9 @@ func NewFilenameFilter(inclusions, exclusions []string) (*FilenameFilter, error)
 		// gets included.
 		dir := path.Dir(include)
 		parts := strings.Split(dir, "/")
-		for i, _ := range parts {
+		for i := range parts {
 			pattern := "/" + filepath.Join(parts[:i+1]...)
-			g, err := filenamesGlobCache.GetGlob(pattern)
+			g, err := GetGlob(pattern)
 			if err != nil {
 				return nil, err
 			}
@@ -72,7 +72,7 @@ func NewFilenameFilter(inclusions, exclusions []string) (*FilenameFilter, error)
 
 	for _, exclude := range exclusions {
 		exclude = normalizeFilenameGlobPattern(exclude)
-		g, err := filenamesGlobCache.GetGlob(exclude)
+		g, err := GetGlob(exclude)
 		if err != nil {
 			return nil, err
 		}
diff --git a/hugofs/glob/filename_filter_test.go b/hugofs/glob/filename_filter_test.go
index 1fce5b135..b74982ef3 100644
--- a/hugofs/glob/filename_filter_test.go
+++ b/hugofs/glob/filename_filter_test.go
@@ -42,6 +42,11 @@ func TestFilenameFilter(t *testing.T) {
 	c.Assert(excludeAllButFooJSON.Match(filepath.FromSlash("/a/b/"), true), qt.Equals, true)
 	c.Assert(excludeAllButFooJSON.Match(filepath.FromSlash("/"), true), qt.Equals, true)
 	c.Assert(excludeAllButFooJSON.Match(filepath.FromSlash("/b"), true), qt.Equals, false)
+
+	excludeAllButFooJSONMixedCasePattern, err := NewFilenameFilter([]string{"/**/Foo.json"}, nil)
+	c.Assert(excludeAllButFooJSONMixedCasePattern.Match(filepath.FromSlash("/a/b/c/d/e/foo.json"), false), qt.Equals, true)
+	c.Assert(excludeAllButFooJSONMixedCasePattern.Match(filepath.FromSlash("/a/b/c/d/e/FOO.json"), false), qt.Equals, true)
+
 	c.Assert(err, qt.IsNil)
 
 	nopFilter, err := NewFilenameFilter(nil, nil)
diff --git a/hugofs/glob/glob.go b/hugofs/glob/glob.go
index 87619802e..841824bcc 100644
--- a/hugofs/glob/glob.go
+++ b/hugofs/glob/glob.go
@@ -33,11 +33,6 @@ var (
 		isWindows: isWindows,
 		cache:     make(map[string]globErr),
 	}
-
-	filenamesGlobCache = &globCache{
-		isWindows: isWindows,
-		cache:     make(map[string]globErr),
-	}
 )
 
 type globErr struct {
@@ -86,10 +81,6 @@ func (gc *globCache) GetGlob(pattern string) (glob.Glob, error) {
 }
 
 type globDecorator struct {
-	// Whether both pattern and the strings to match will be matched
-	// by their original case.
-	isCaseSensitive bool
-
 	// On Windows we may get filenames with Windows slashes to match,
 	// which wee need to normalize.
 	isWindows bool
@@ -101,14 +92,12 @@ func (g globDecorator) Match(s string) bool {
 	if g.isWindows {
 		s = filepath.ToSlash(s)
 	}
-	if !g.isCaseSensitive {
-		s = strings.ToLower(s)
-	}
+	s = strings.ToLower(s)
 	return g.g.Match(s)
 }
 
 type globDecoratorDouble struct {
-	lowerCase   glob.Glob
+	lowerCase    glob.Glob
 	originalCase glob.Glob
 }
 
@@ -120,34 +109,11 @@ func GetGlob(pattern string) (glob.Glob, error) {
 	return defaultGlobCache.GetGlob(pattern)
 }
 
-func GetFilenamesGlob(pattern string) (glob.Glob, error) {
-	lowered := strings.ToLower(pattern)
-	hasUpperCase := pattern != lowered
-	gLowered, err := filenamesGlobCache.GetGlob(lowered)
-	if err != nil {
-		return nil, err
-	}
-
-	if !hasUpperCase {
-		return gLowered, nil
-	}
-
-	gSensitive, err := filenamesGlobCache.GetGlob(pattern)
-	if err != nil {
-		return nil, err
-	}
-	return globDecoratorDouble{
-		lowerCase:   gLowered,
-		originalCase: gSensitive,
-	}, nil
-
-}
-
 func NormalizePath(p string) string {
-	return strings.Trim(path.Clean(filepath.ToSlash(strings.ToLower(p))), "/.")
+	return strings.ToLower(NormalizePathNoLower(p))
 }
 
-func NormalizePathCaseSensitive(p string) string {
+func NormalizePathNoLower(p string) string {
 	return strings.Trim(path.Clean(filepath.ToSlash(p)), "/.")
 }
 
diff --git a/hugofs/glob/glob_test.go b/hugofs/glob/glob_test.go
index 66efe9e53..d40e16edc 100644
--- a/hugofs/glob/glob_test.go
+++ b/hugofs/glob/glob_test.go
@@ -66,7 +66,7 @@ func TestNormalizePath(t *testing.T) {
 }
 
 func TestGetGlob(t *testing.T) {
-	for _, cache := range []*globCache{defaultGlobCache, filenamesGlobCache} {
+	for _, cache := range []*globCache{defaultGlobCache} {
 		c := qt.New(t)
 		g, err := cache.GetGlob("**.JSON")
 		c.Assert(err, qt.IsNil)
@@ -89,8 +89,8 @@ func BenchmarkGetGlob(b *testing.B) {
 	}
 
 	runBench("Default cache", defaultGlobCache, "abcde")
-	runBench("Filenames cache, lowercase searchs", filenamesGlobCache, "abcde")
-	runBench("Filenames cache, mixed case searchs", filenamesGlobCache, "abCDe")
+	runBench("Filenames cache, lowercase searchs", defaultGlobCache, "abcde")
+	runBench("Filenames cache, mixed case searchs", defaultGlobCache, "abCDe")
 
 	b.Run("GetGlob", func(b *testing.B) {
 		for i := 0; i < b.N; i++ {
diff --git a/hugofs/glob_test.go b/hugofs/glob_test.go
index fbb276445..a6ae85fc8 100644
--- a/hugofs/glob_test.go
+++ b/hugofs/glob_test.go
@@ -52,14 +52,16 @@ func TestGlob(t *testing.T) {
 	create("UPPER/sub/style.css")
 	create("root/UPPER/sub/style.css")
 
+	c.Assert(collect(filepath.FromSlash("/jsonfiles/*.json")), qt.HasLen, 2)
+
 	c.Assert(collect("**.json"), qt.HasLen, 5)
 	c.Assert(collect("**"), qt.HasLen, 8)
 	c.Assert(collect(""), qt.HasLen, 0)
 	c.Assert(collect("jsonfiles/*.json"), qt.HasLen, 2)
 	c.Assert(collect("*.json"), qt.HasLen, 1)
 	c.Assert(collect("**.xml"), qt.HasLen, 1)
-	c.Assert(collect(filepath.FromSlash("/jsonfiles/*.json")), qt.HasLen, 2)
-	c.Assert(collect("UPPER/sub/style.css"), qt.HasLen, 1)
+
 	c.Assert(collect("root/UPPER/sub/style.css"), qt.HasLen, 1)
+	c.Assert(collect("UPPER/sub/style.css"), qt.HasLen, 1)
 
 }
diff --git a/resources/resource_factories/create/create.go b/resources/resource_factories/create/create.go
index 508c141f6..075d25736 100644
--- a/resources/resource_factories/create/create.go
+++ b/resources/resource_factories/create/create.go
@@ -93,7 +93,7 @@ func (c *Client) GetMatch(pattern string) (resource.Resource, error) {
 }
 
 func (c *Client) match(name, pattern string, matchFunc func(r resource.Resource) bool, firstOnly bool) (resource.Resources, error) {
-	pattern = glob.NormalizePathCaseSensitive(pattern)
+	pattern = glob.NormalizePath(pattern)
 	partitions := glob.FilterGlobParts(strings.Split(pattern, "/"))
 	if len(partitions) == 0 {
 		partitions = []string{resources.CACHE_OTHER}