MB-5582 Remove unncessary locking on vbucket_set_state mutex
MB-5582 Remove unncessary locking on vbucket_set_state mutex

Change-Id: Ifc0c39d4d5e0add2bea4ffa3ec8e52226f229d18
Reviewed-on: http://review.couchbase.org/17298
Reviewed-by: Michael Wiederhold <a17fed27eaa842282862ff7c1b9c8395a26ac320@couchbase.com>
Tested-by: Chiyoung Seo <8b279095f11c26cc21045fda5a3e51debb005aa9@gmail.com>

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