tunnels: harmonize cleanup done on skb on xmit path

The goal of this patch is to harmonize cleanup done on a skbuff on xmit path.
Before this patch, behaviors were different depending of the tunnel type.

Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv6/sit.c b/net/ipv6/sit.c
index b2e44f4..82b425b 100644
--- a/net/ipv6/sit.c
+++ b/net/ipv6/sit.c
@@ -860,9 +860,6 @@
 			tunnel->err_count = 0;
 	}
 
-	if (!net_eq(tunnel->net, dev_net(dev)))
-		skb_scrub_packet(skb, true);
-
 	/*
 	 * Okay, now see if we can stuff it in the buffer as-is.
 	 */
@@ -889,7 +886,7 @@
 	tos = INET_ECN_encapsulate(tos, ipv6_get_dsfield(iph6));
 
 	err = iptunnel_xmit(rt, skb, fl4.saddr, fl4.daddr, IPPROTO_IPV6, tos,
-			    ttl, df);
+			    ttl, df, !net_eq(tunnel->net, dev_net(dev)));
 	iptunnel_xmit_stats(err, &dev->stats, dev->tstats);
 	return NETDEV_TX_OK;