Make fog accept user in format Domain\username or username@domain for the ad joining features.  If there's no Domain\ or @domain field, it should send the domain with the username, otherwise just send the data as is.

git-svn-id: https://svn.code.sf.net/p/freeghost/code/trunk@2289 71f96598-fa45-0410-b640-bcd6f8691b32
Merge svn with master