ticket 1576 - problem where a group admin could not add a limited access user. The change is version 1.29 was a little too restrictive. The site-admin check should only be if can_browse_p =0. Also, I changed the defaults for can_browse_p and read_private_data_p to be the most restrictive (it is standard for security to make defaults the most restrictive and then require extra work to add the privileges