MB-4930 Dispatcher may deadlock itself during shutdown
MB-4930 Dispatcher may deadlock itself during shutdown

Change-Id: I204c0553d8151be2c7d2f6898ca19275254d7d89
Reviewed-on: http://review.couchbase.org/14170
Reviewed-by: Chiyoung Seo <8b279095f11c26cc21045fda5a3e51debb005aa9@gmail.com>
Tested-by: Chiyoung Seo <8b279095f11c26cc21045fda5a3e51debb005aa9@gmail.com>

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