Clear the stats values before calling stat
Clear the stats values before calling stat

Change-Id: Ic626bdec3ac0b5fe9ca63a3700029cfd677fbe80
Reviewed-on: http://review.northscale.com/2228
Reviewed-by: Dustin Sallings <1c08efb9b3965701be9d700d9a6f481f1ffec3ea@spy.net>
Tested-by: Dustin Sallings <1c08efb9b3965701be9d700d9a6f481f1ffec3ea@spy.net>

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