Upgrading Spymemcached to 2.11.3

Change-Id: I7b51952195a55c69d70ef151e493cd5d36c447a8
Reviewed-on: http://review.couchbase.org/37903
Reviewed-by: Michael Nitschinger <michael.nitschinger@couchbase.com>
Tested-by: Michael Nitschinger <michael.nitschinger@couchbase.com>