Improved error handling for invalid model parameters that aren't custom functions.
Improved error handling for invalid model parameters that aren't custom functions.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@502 bcc190cf-cafb-0310-a4f2-bffc1f526a37

--HG--
extra : convert_revision : 23c76848920215e46f1e0c8cd8072d54c13d08d4

heracek/django-nonrel,adieu/django-nonrel,heracek/django-nonrel,adieu/django-nonrel,adieu/django-nonrel,heracek/django-nonrel