[PATCH] use EOPNOTSUPP instead of EINVAL if the conntrack has no helper

This patch changes the return value if the conntrack has no helper assigned.
Instead of EINVAL, which is reserved for malformed messages, it returns 
EOPNOTSUPP.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

Index: net-next-2.6.git/net/netfilter/nf_conntrack_netlink.c
===================================================================
--- net-next-2.6.git.orig/net/netfilter/nf_conntrack_netlink.c	2008-07-31 11:40:32.000000000 +0200
+++ net-next-2.6.git/net/netfilter/nf_conntrack_netlink.c	2008-07-31 11:40:40.000000000 +0200
@@ -1694,7 +1694,7 @@ ctnetlink_create_expect(struct nlattr *c
 
 	if (!help || !help->helper) {
 		/* such conntrack hasn't got any helper, abort */
-		err = -EINVAL;
+		err = -EOPNOTSUPP;
 		goto out;
 	}