[1.2.X] Fixed #13241. order_with_respect_to now works with ForeignKeys who...

[1.2.X] Fixed #13241.  order_with_respect_to now works with ForeignKeys who refer to their model lazily (i.e. with a string).  Thanks to Gabriel Grant for the patch.  This is a backport of [14045].

git-svn-id: http://code.djangoproject.com/svn/django/branches/releases/1.2.X@14046 bcc190cf-cafb-0310-a4f2-bffc1f526a37