Correct unit for time while waiting for stat
Correct unit for time while waiting for stat

useconds_t => us (microseconds)

Change-Id: Ifa493449121e69b9f945f0c5b4a0580a0b682c62
Reviewed-on: http://review.couchbase.org/58596
Reviewed-by: Dave Rigby <a09264da4832c7ff1d3bf1608a19f4b870f93750@couchbase.com>
Tested-by: buildbot <80754af91bfb6d1073585b046fe0a474ce868509@couchbase.com>

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