Fix the mock_file test helper.

git-svn-id: svn+ssh://rubyforge.org/var/svn/redmine/trunk@4010 e93f8b46-1217-0410-a6f0-8f06a7374b81

test/exemplars/attachment_exemplar.rb

@@ -12,6 +12,6 @@ class Attachment < ActiveRecord::Base
   end
 
   def self.generate_file
-    @file = mock_file
+    @file = ActiveSupport::TestCase.mock_file
   end
 end