MB-11698: Release reference to all connections in upr upon shutdown
MB-11698: Release reference to all connections in upr upon shutdown

Change-Id: I5759f89dcf1faaa5f7902fdb8fa08604a34f5814
Reviewed-on: http://review.couchbase.org/39514
Reviewed-by: Chiyoung Seo <fcffc23db27b19ee4ebba46695ee6b50e09216a2@couchbase.com>
Tested-by: abhinav dangeti <d73ef2279de6577f7bf081737ee47554bbb7dc82@couchbase.com>

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