Fixed #15544 -- Corrected a test failure in the generic views tests that...

Fixed #15544 -- Corrected a test failure in the generic views tests that depended on primary key allocation. Thanks to Łukasz Rekucki for the report.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@15742 bcc190cf-cafb-0310-a4f2-bffc1f526a37