Fixed #15206 -- Added select_related call to the permissions field of the...

Fixed #15206 -- Added select_related call to the permissions field of the GroupAdmin to lower the number of queries. Thanks, Chris Adams.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@16620 bcc190cf-cafb-0310-a4f2-bffc1f526a37