Don't use unique_ptr for the mech infos
Don't use unique_ptr for the mech infos

We've stored std::unique_ptr in a std::array we access from
multiple threads (without any locking), but we should be
accessing it in a "read only modus" which shouldn't be
modifying any of the internal data in the object. I am
suspecting that to be the reason for things to fail on
windows (it could be that it actually does)

Change-Id: I337601a95063c213775843dcac8cdf03fbf65b9f
Reviewed-on: http://review.couchbase.org/59648
Tested-by: buildbot <80754af91bfb6d1073585b046fe0a474ce868509@couchbase.com>
Reviewed-by: Dave Rigby <a09264da4832c7ff1d3bf1608a19f4b870f93750@couchbase.com>

daverigby/kv_engine,couchbase/memcached,couchbase/memcached,daverigby/memcached,owendCB/memcached,daverigby/kv_engine,owendCB/memcached,daverigby/memcached,owendCB/memcached,daverigby/kv_engine,daverigby/kv_engine,daverigby/memcached,couchbase/memcached,owendCB/memcached,couchbase/memcached,daverigby/memcached