Lock the entire buckets array when traversing it
Lock the entire buckets array when traversing it

Change-Id: I518b3f89559c7a5a44b74efb148af7c680700fc2
Reviewed-on: http://review.couchbase.org/55908
Tested-by: buildbot <80754af91bfb6d1073585b046fe0a474ce868509@couchbase.com>
Reviewed-by: Jim Walker <1cd02e31b43620d7c664e038ca42a060d61727b9@couchbase.com>

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