Fixed #2084 -- Removed admin-site 'documentation / change password / log out'...

Fixed #2084 -- Removed admin-site 'documentation / change password / log out' links on login page for users who are logged in but don't have staff status. Thanks, rudolphfroger

git-svn-id: http://code.djangoproject.com/svn/django/trunk@3079 bcc190cf-cafb-0310-a4f2-bffc1f526a37