[1.2.X] Fixed #15554 -- Corrected test failure in contenttypes when default...

[1.2.X] Fixed #15554 -- Corrected test failure in contenttypes when default site isn't example.com. Thanks to twil for the report, and PaulM for the patch.

Backport of r15766 from trunk.

git-svn-id: http://code.djangoproject.com/svn/django/branches/releases/1.2.X@15767 bcc190cf-cafb-0310-a4f2-bffc1f526a37