clientv3: non-recursive watch
clientv3: non-recursive watch

Signed-off-by: Ted Yu <22f3e725b314afeca4d45e12683c560674029d21@gmail.com>

ajityagaty/etcd,mqliang/etcd,gyuho/etcd,dannysauer/etcd,gyuho/etcd,mkumatag/etcd,mqliang/etcd,li-ang/etcd,mkumatag/etcd,coreos/etcd,cockroachdb/etcd,li-ang/etcd,etcd-io/etcd,coreos/etcd,ajityagaty/etcd,etcd-io/etcd,mqliang/etcd,ajityagaty/etcd,rnaveiras/etcd,rnaveiras/etcd,etcd-io/etcd,cockroachdb/etcd,rnaveiras/etcd,mkumatag/etcd,dannysauer/etcd