Updated `clean_paths` and `expand_paths` methods to use `File::FNM_CASEFOLD`

This change is an update to an earlier pull request to fix Issue
https://github.com/CocoaPods/CocoaPods/pull/572.

lib/cocoapods/local_pod.rb

@@ -166,10 +166,11 @@ module Pod
     # @note The Paths are downcased to prevent issues. See #568.
     #
     def clean_paths
-      files = Dir.glob(root + "**/*", File::FNM_DOTMATCH)
+      used = used_files.map(&:downcase)
+      files = Dir.glob(root + "**/*", [File::FNM_DOTMATCH, File::FNM_CASEFOLD])
 
       files.reject! do |candidate|
-        candidate.end_with?('.', '..') || used_files.any? do |path|
+        candidate.end_with?('.', '..') || used.any? do |path|
           path.include?(candidate) || candidate.include?(path)
         end
       end
@@ -535,7 +536,7 @@ module Pod
         if pattern.directory? && options[:glob]
           pattern += options[:glob]
         end
-        Pathname.glob(pattern)
+        Pathname.glob(pattern, File::FNM_CASEFOLD)
       end.flatten
     end