[1.0.X] Fixed #8752 -- Fixed django.contrib.auth tests to be locale-independent.

Patch from Koen Biermans.

Backport of r10599 from trunk.

git-svn-id: http://code.djangoproject.com/svn/django/branches/releases/1.0.X@10600 bcc190cf-cafb-0310-a4f2-bffc1f526a37