Fixed #4783: Added a note that "admin media" means "media used by the admin...

Fixed #4783: Added a note that "admin media" means "media used by the admin app", and that ADMIN_MEDIA_PREFIX and MEDIA_URL should not be the same value.


git-svn-id: http://code.djangoproject.com/svn/django/trunk@7312 bcc190cf-cafb-0310-a4f2-bffc1f526a37