MB-12359: Disable SSLv2 & SSLv3 due to the POODLE exploit

Change-Id: I157226cf5fcf1170fc5381923926667345f19ee2
Reviewed-on: http://review.couchbase.org/42199
Reviewed-by: Dave Rigby <daver@couchbase.com>
Tested-by: Trond Norbye <trond.norbye@gmail.com>