ipip: Fix bug added to ipip_tunnel_xmit().

We can remove the rt_gateway == 0 check but we shouldn't
remove the 'dst' initialization too.

Noticed by Eric Dumazet.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/ipv4/ipip.c

@@ -454,6 +454,7 @@ static netdev_tx_t ipip_tunnel_xmit(struct sk_buff *skb, struct net_device *dev)
 			dev->stats.tx_fifo_errors++;
 			goto tx_error;
 		}
+		dst = rt->rt_gateway;
 	}
 
 	rt = ip_route_output_ports(dev_net(dev), &fl4, NULL,