Fixed #14994 - Add attributes to example auth backend which would emit...

Fixed #14994 - Add attributes to example auth backend which would emit DeprecationWarning otherwise. Thanks kmike for the report and ojii for the patch.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@15137 bcc190cf-cafb-0310-a4f2-bffc1f526a37