Fixed #16818 -- Fixed ORM bug with many-to-many add() method where it wasn't...

Fixed #16818 -- Fixed ORM bug with many-to-many add() method where it wasn't committing the change. Thanks, pressureman and kmtracey

git-svn-id: http://code.djangoproject.com/svn/django/trunk@17189 bcc190cf-cafb-0310-a4f2-bffc1f526a37