Remove lcb_server_t name. Use only mc_SERVER

Change-Id: I24071eab1c396c88f08ae7df0270c167e49453b8
Reviewed-on: http://review.couchbase.org/39382
Tested-by: Mark Nunberg <mnunberg@haskalah.org>
Reviewed-by: Brett Lawson <brett19@gmail.com>