[NETFILTER] nf_queue: Fix Ooops when no queue handler registered

With the new nf_queue generalization in 2.6.14, we've introduced a bug
that causes an oops as soon as a packet is queued but no queue handler
registered.  This patch fixes it.
Signed-off-by: Harald Welte <laforge@netfilter.org>
Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>

net/netfilter/nf_queue.c

@@ -117,7 +117,7 @@ int nf_queue(struct sk_buff **skb,
 
 	/* QUEUE == DROP if noone is waiting, to be safe. */
 	read_lock(&queue_handler_lock);
-	if (!queue_handler[pf]->outfn) {
+	if (!queue_handler[pf] || !queue_handler[pf]->outfn) {
 		read_unlock(&queue_handler_lock);
 		kfree_skb(*skb);
 		return 1;