netfilter: netns nf_conntrack: pass netns pointer to L4 protocol's ->error hook

Again, it's deducible from skb, but we're going to use it for
nf_conntrack_checksum and statistics, so just pass it from upper layer.

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>
diff --git a/net/netfilter/nf_conntrack_proto_tcp.c b/net/netfilter/nf_conntrack_proto_tcp.c
index 539a820..4e71de2 100644
--- a/net/netfilter/nf_conntrack_proto_tcp.c
+++ b/net/netfilter/nf_conntrack_proto_tcp.c
@@ -746,7 +746,8 @@
 };
 
 /* Protect conntrack agaist broken packets. Code taken from ipt_unclean.c.  */
-static int tcp_error(struct sk_buff *skb,
+static int tcp_error(struct net *net,
+		     struct sk_buff *skb,
 		     unsigned int dataoff,
 		     enum ip_conntrack_info *ctinfo,
 		     u_int8_t pf,