Fix failing active record store tests

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@7317 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

actionpack/lib/action_controller/session/active_record_store.rb

@@ -122,13 +122,14 @@ def data
           @data ||= self.class.unmarshal(read_attribute(@@data_column_name)) || {}
         end
 
+        attr_writer :data
+
         # Has the session been loaded yet?
         def loaded?
           !! @data
         end
 
         private
-          attr_writer :data
 
           def marshal_data!
             return false if !loaded?