Fixed #10069 -- Fixed the model form unique validation code to not proceed...

Fixed #10069 -- Fixed the model form unique validation code to not proceed with using, for example, RelatedObjects returned by get_field_by_name as though they were model Fields.


git-svn-id: http://code.djangoproject.com/svn/django/trunk@9777 bcc190cf-cafb-0310-a4f2-bffc1f526a37