Fixed #16644 -- Fixed one additional test that was failing in Oracle due to...

Fixed #16644 -- Fixed one additional test that was failing in Oracle due to false assumptions about the primary keys of objects. Thanks Aymeric Augustin for report and patch.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@16636 bcc190cf-cafb-0310-a4f2-bffc1f526a37