routing+lnrpc: fix log statements

lnrpc/routerrpc/router_server.go

@@ -1313,7 +1313,7 @@ func (s *Server) trackPayment(subscription routing.ControlTowerSubscriber,
 
 	// Otherwise, we will log and return the error as the stream has
 	// received an error from the payment lifecycle.
-	log.Errorf("TrackPayment got error for payment %x: %v", identifier, err)
+	log.Errorf("TrackPayment got error for payment %v: %v", identifier, err)
 
 	return err
 }