Fixed #13334: Restored ability to load template tags from eggs. Again thanks...

Fixed #13334: Restored ability to load template tags from eggs. Again thanks Ramiro and metzen for pointers on how to find out if a module loaded from an egg has a particular submodule, and Russ for review.


git-svn-id: http://code.djangoproject.com/svn/django/trunk@12986 bcc190cf-cafb-0310-a4f2-bffc1f526a37