[1.0.X] Fixed #10774: accessing form media types in templates (i.e. ``{{...

[1.0.X] Fixed #10774: accessing form media types in templates (i.e. ``{{ form.media.js }}``) now works. Thanks, tarequeh and Alex Gaynor. Backport of r10489 from trunk.

git-svn-id: http://code.djangoproject.com/svn/django/branches/releases/1.0.X@10491 bcc190cf-cafb-0310-a4f2-bffc1f526a37