MB-19732: Only update sendTime if successfully send noop
MB-19732: Only update sendTime if successfully send noop

In the maybeSendNoop function when a DCP producer attempts
to send a noop to a consumer it can receive back
ENGINE_SUCCESS or ENGINE_E2BIG.

We should only set pendingRecv to true and update the
last sendTime if ENGINE_SUCCESS is returned.

Change-Id: Ice8a66dcae35505d7bab7d261f080d5ffb95c8e3
Reviewed-on: http://review.couchbase.org/64724
Well-Formed: buildbot <80754af91bfb6d1073585b046fe0a474ce868509@couchbase.com>
Reviewed-by: Manu Dhundi <158873d90a7ef40f3637a222b7329c09d0222554@couchbase.com>
Tested-by: buildbot <80754af91bfb6d1073585b046fe0a474ce868509@couchbase.com>
Reviewed-by: Dave Rigby <a09264da4832c7ff1d3bf1608a19f4b870f93750@couchbase.com>

couchbase/ep-engine,daverigby/ep-engine,membase/ep-engine,daverigby/ep-engine,membase/ep-engine,teligent-ru/ep-engine,daverigby/kv_engine,daverigby/kv_engine,membase/ep-engine,couchbase/ep-engine,couchbase/ep-engine,daverigby/ep-engine,daverigby/ep-engine,couchbase/ep-engine,teligent-ru/ep-engine,teligent-ru/ep-engine,daverigby/kv_engine,membase/ep-engine,daverigby/kv_engine,teligent-ru/ep-engine