[1.2.X] Fixed #13961 - note that reverse URL lookups can't be done within a...

[1.2.X] Fixed #13961 - note that reverse URL lookups can't be done within a blocktrans tag. Thanks garrison for the report and richardb and zerok for work on the patch.

Backport of r15100 from trunk.

git-svn-id: http://code.djangoproject.com/svn/django/branches/releases/1.2.X@15101 bcc190cf-cafb-0310-a4f2-bffc1f526a37