Timings should only be collected for ClientRequest messages
Timings should only be collected for ClientRequest messages

The state machinery in memcached calls mcbp_collect_timings
as part of the state transitions. The same state diagram
is however used to handle ServerResponse messages, and
all counting be ignored (as that would reflect the time
spent processing the server response message)

Change-Id: Ic5d4bc6acc582b157f7257524acd5ea589970cdf
Reviewed-on: http://review.couchbase.org/99661
Tested-by: Build Bot <80754af91bfb6d1073585b046fe0a474ce868509@couchbase.com>
Reviewed-by: Jim Walker <1cd02e31b43620d7c664e038ca42a060d61727b9@couchbase.com>

daverigby/kv_engine,daverigby/kv_engine,daverigby/kv_engine,daverigby/kv_engine