Upgrade spymemcached to 2.11.2

Change-Id: I2209edf896c448b4b14e71572866fd5057a1de30
Reviewed-on: http://review.couchbase.org/36829
Reviewed-by: Michael Nitschinger <michael.nitschinger@couchbase.com>
Tested-by: Michael Nitschinger <michael.nitschinger@couchbase.com>