JavaScriptVariableProxy#to_json ignores the options arg

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@7831 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

actionpack/lib/action_view/helpers/prototype_helper.rb

@@ -867,7 +867,7 @@ module ActionView
         true
       end
 
-      def to_json
+      def to_json(options = nil)
         @variable
       end