Fixed #17327 (again) -- Moved createsuperuser tests added in r17665.

In their new location they won't cause multi-db-related errors when
users run contrib.auh tests together with their application tests.

Thanks brianriley for the patch.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@17676 bcc190cf-cafb-0310-a4f2-bffc1f526a37