etcdserver: update corrupt hash detection's logic
etcdserver: update corrupt hash detection's logic

get peer's hash using the same revision as the value used by leader

Signed-off-by: Benjamin Wang <a1713d12b1b05630690f22cadfd282d625d8acb2@vmware.com>

etcd-io/etcd,ajityagaty/etcd,ajityagaty/etcd,etcd-io/etcd,ajityagaty/etcd,etcd-io/etcd