fix cname for doc.wikimedia.org

Luckily, this didn't go live, but I did already merge the bad change in
Ie80551a532dbc32cbc9c0d73c396e88f63fcb0b3.  this fixes it

Change-Id: Ie483903b6f77270a4295672b5a0a5f6a2375e3e4
RT: 6594