ip_tunnel: Remove double unregister of the fallback device

When queueing the netdevices for removal, we queue the
fallback device twice in ip_tunnel_destroy(). The first
time when we queue all netdevices in the namespace and
then again explicitly. Fix this by removing the explicit
queueing of the fallback device.

Bug was introduced when network namespace support was added
with commit 6c742e71 ("ipip: add x-netns support").

Cc: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: NSteffen Klassert <steffen.klassert@secunet.com>
Acked-by: NNicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/ipv4/ip_tunnel.c

@@ -886,8 +886,6 @@ static void ip_tunnel_destroy(struct ip_tunnel_net *itn, struct list_head *head,
 			if (!net_eq(dev_net(t->dev), net))
 				unregister_netdevice_queue(t->dev, head);
 	}
-	if (itn->fb_tunnel_dev)
-		unregister_netdevice_queue(itn->fb_tunnel_dev, head);
 }
 
 void ip_tunnel_delete_net(struct ip_tunnel_net *itn, struct rtnl_link_ops *ops)