net, ip_tunnel: fix namespaces move

in the same manner as commit 690afc16 ("net: ip6_gre: fix moving
ip6gre between namespaces"), fix namespace moving as it was broken since
commit 2e15ea39 ("ip_gre: Add support to collect tunnel metadata.").
Indeed, the ip6_gre commit removed the local flag for collect_md
condition, so there is no reason to keep it for ip_gre/ip_tunnel.

this patch will fix both ip_tunnel and ip_gre modules.

Fixes: 2e15ea39 ("ip_gre: Add support to collect tunnel metadata.")
Signed-off-by: NWilliam Dauchy <w.dauchy@criteo.com>
Acked-by: NNicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/ipv4/ip_tunnel.c

@@ -1236,10 +1236,8 @@ int ip_tunnel_init(struct net_device *dev)
 	iph->version		= 4;
 	iph->ihl		= 5;
 
-	if (tunnel->collect_md) {
-		dev->features |= NETIF_F_NETNS_LOCAL;
+	if (tunnel->collect_md)
 		netif_keep_dst(dev);
-	}
 	return 0;
 }
 EXPORT_SYMBOL_GPL(ip_tunnel_init);