[1.2.X] Fixed #15368 - test failures due to regression with RequestContext

Thanks to cyberdelia for the reports on this.

Backport of [15660] from trunk.

git-svn-id: http://code.djangoproject.com/svn/django/branches/releases/1.2.X@15661 bcc190cf-cafb-0310-a4f2-bffc1f526a37