CCBC-414: Assign cccp cookie when sending over server struct

We never assigned to cccp->cmdcookie

Change-Id: I66c1683e5934f5259d4c7bc6c3995d628cd8690f
Reviewed-on: http://review.couchbase.org/37386
Tested-by: Mark Nunberg <mnunberg@haskalah.org>
Reviewed-by: Brett Lawson <brett19@gmail.com>