Use Mash to handle string and symbol keys

Users may pass string instead of symbol in the permissions hashes, the
resource should either fail or handle them properly.

This patch propose to handle them properly using Chef Mash.
Before this patch the resource was not idempotent as during the 2nd run,
a diff was computed, something similar to:
  -'user'
  +:user

resources/facl.rb

@@ -45,13 +45,13 @@
 action :set do
   raise "Cannot set ACL because File #{new_resource.path} does not exist!" unless ::File.exist?(new_resource.path)
 
-  new_resource.facl = {
-    user: new_resource.user.is_a?(String) ? {:'' => new_resource.user} : new_resource.user,
-    group: new_resource.group.is_a?(String) ? {:'' => new_resource.group} : new_resource.group,
-    other: new_resource.other.is_a?(String) ? {:'' => new_resource.other} : new_resource.other,
-    mask: new_resource.mask.is_a?(String) ? {:'' => new_resource.mask} : new_resource.mask,
+  new_resource.facl = ::Mash.new(
+    user: new_resource.user.is_a?(String) ? {'' => new_resource.user} : new_resource.user,
+    group: new_resource.group.is_a?(String) ? {'' => new_resource.group} : new_resource.group,
+    other: new_resource.other.is_a?(String) ? {'' => new_resource.other} : new_resource.other,
+    mask: new_resource.mask.is_a?(String) ? {'' => new_resource.mask} : new_resource.mask,
     default: new_resource.default,
-  }
+  )
   # If there are no default acl entries for things, specify blank hashes so diff_facl works
   [:user, :group, :other, :mask].each do |symbol|
     new_resource.facl[:default][symbol] = {} unless new_resource.facl[:default].key?(symbol)
@@ -65,7 +65,7 @@
   changes_required = diff_facl(current_resource.facl, new_resource.facl)
   # Don't try to remove parts of the base ACL, it cannot be removed.
   [:user, :group, :other, :mask].each do |symbol|
-    changes_required[symbol].delete_if { |key,value| key.eql?(:'') and value.eql?(:remove) } if changes_required[symbol]
+    changes_required[symbol].delete_if { |key,value| key.eql?('') and value.eql?(:remove) } if changes_required[symbol]
   end
   Chef::Log.debug("Changes Required: #{changes_required}")
   default = changes_required.delete(:default)
@@ -91,7 +91,7 @@
 end
 
 def facl_to_hash(string)
-  facl = { default: {}, user: {}, group: {}, mask: {}, other: {} }
+  facl = ::Mash.new(default: {}, user: {}, group: {}, mask: {}, other: {})
   string.each_line do |line|
     next unless line =~ /^(default|user|group|mask|other):/
     l = line.split(':')
@@ -108,7 +108,7 @@ def facl_to_hash(string)
 end
 
 def diff_facl(cur_r, new_r)
-  diff = {}
+  diff = ::Mash.new
   (cur_r.keys - new_r.keys).each do |k|
     diff[k] = :remove
   end