GTA: simpler veh2net (sfinktah)

//better veh2net

        auto veh2net = VEH_TO_NET(veh);
        if (NETWORK_HAS_CONTROL_OF_NETWORK_ID(veh2net)) {
            // 1
            SET_NETWORK_ID_CAN_MIGRATE(veh2net, 1);
            SET_NETWORK_ID_EXISTS_ON_ALL_MACHINES(veh2net, 1);
        }