Add support for using SSL to mcstat

Change-Id: I504b53a7054918ade9b1f50f875e4fc8f061fdd2
Reviewed-on: http://review.couchbase.org/33070
Reviewed-by: Trond Norbye <trond.norbye@gmail.com>
Tested-by: Trond Norbye <trond.norbye@gmail.com>