[1.2.X] Fixed #14176 -- Added forwards compatibility to the legacy syndication...

[1.2.X] Fixed #14176 -- Added forwards compatibility to the legacy syndication feed view. This allows class-based feeds to be deployed using the old-style feed view, as long as the feed requires no arguments (i.e., get_object returns None). Thanks to psychcf for the report, cwhaines for the investigation, and Andrew Godwin for the assist.

Backport of r15189 from trunk.

git-svn-id: http://code.djangoproject.com/svn/django/branches/releases/1.2.X@15190 bcc190cf-cafb-0310-a4f2-bffc1f526a37