[1.2.X] Fixed #15548 -- Added an ordering clause to prevent test failures...

[1.2.X] Fixed #15548 -- Added an ordering clause to prevent test failures under Postgres. Thanks to bberes for the report.

Backport of r15743 from trunk.

git-svn-id: http://code.djangoproject.com/svn/django/branches/releases/1.2.X@15746 bcc190cf-cafb-0310-a4f2-bffc1f526a37