etcdserver: support Revision option in v3 RangeRequest

etcdserver/v3demo_server.go

@@ -252,12 +252,12 @@ func applyRange(txnID int64, kv dstorage.KV, r *pb.RangeRequest) (*pb.RangeRespo
 	}
 
 	if txnID != noTxn {
-		kvs, rev, err = kv.TxnRange(txnID, r.Key, r.RangeEnd, limit, 0)
+		kvs, rev, err = kv.TxnRange(txnID, r.Key, r.RangeEnd, limit, r.Revision)
 		if err != nil {
 			return nil, err
 		}
 	} else {
-		kvs, rev, err = kv.Range(r.Key, r.RangeEnd, limit, 0)
+		kvs, rev, err = kv.Range(r.Key, r.RangeEnd, limit, r.Revision)
 		if err != nil {
 			return nil, err
 		}