The first step in fixing a group of problems related to outputting a proper

"value" for a field that is a relation to another model.

This part adds the utility method on Model that should help in general.Also
cleans up the slightly ugly mess from r8957.


git-svn-id: http://code.djangoproject.com/svn/django/trunk@9601 bcc190cf-cafb-0310-a4f2-bffc1f526a37