Add validation function for vbucket state
Add validation function for vbucket state

owendCB/memcached,daverigby/kv_engine,mrkwse/memcached,abhinavdangeti/memcached,Metaswitch/memcached,cloudrain21/memcached-1,Metaswitch/memcached,zbase/memcached,mrkwse/memcached,mrkwse/memcached,couchbase/memcached,abhinavdangeti/memcached,daverigby/kv_engine,zbase/memcached,daverigby/kv_engine,owendCB/memcached,jimwwalker/memcached,couchbase/memcached,Metaswitch/memcached,couchbase/memcached,daverigby/memcached,cloudrain21/memcached-1,Metaswitch/memcached,zbase/memcached,jimwwalker/memcached,daverigby/memcached,abhinavdangeti/memcached,Metaswitch/memcached,daverigby/memcached,jimwwalker/memcached,owendCB/memcached,cloudrain21/memcached-1,owendCB/memcached,daverigby/memcached,abhinavdangeti/memcached,daverigby/kv_engine,zbase/memcached,zbase/memcached,abhinavdangeti/memcached,mrkwse/memcached,cloudrain21/memcached-1,couchbase/memcached