always send the leader info on each heartbeat

weed/server/master_grpc_server.go

@@ -66,7 +66,7 @@ func (ms MasterServer) SendHeartbeat(stream pb.Seaweed_SendHeartbeatServer) erro
 			return err
 		}
 
-		if !t.IsLeader() {
+		// tell the volume servers about the leader
 		newLeader, err := t.Leader()
 		if err == nil {
 			if err := stream.Send(&pb.HeartbeatResponse{
@@ -76,6 +76,4 @@ func (ms MasterServer) SendHeartbeat(stream pb.Seaweed_SendHeartbeatServer) erro
 			}
 		}
 	}
-
-	}
 }