Fixed #2189 -- Optimized auth.User.get_all_permissions() to use select_related...

Fixed #2189 -- Optimized auth.User.get_all_permissions() to use select_related behind the scenes to avoid multiple queries. Thanks, konrad@gwu.edu

git-svn-id: http://code.djangoproject.com/svn/django/trunk@3162 bcc190cf-cafb-0310-a4f2-bffc1f526a37