[IPV6]: Clean skb cb on IPv6 input.

Clear the accumulated junk in IP6CB when starting to handle an IPV6
packet.
Signed-off-by: Guillaume Chazarain <guichaz@yahoo.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv6/ip6_input.c

@@ -71,6 +71,8 @@ int ipv6_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt
 		goto out;
 	}
 
+	memset(IP6CB(skb), 0, sizeof(struct inet6_skb_parm));
+
 	/*
 	 * Store incoming device index. When the packet will
 	 * be queued, we cannot refer to skb->dev anymore.