netfilter: ip6t_REJECT: fix a dst leak in ipv6 REJECT

We should release dst if dst->error is set.

Bug introduced in 2.6.14 by commit e104411
([XFRM]: Always release dst_entry on error in xfrm_lookup)

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Cc: stable@kernel.org
Signed-off-by: Patrick McHardy <kaber@trash.net>

net/ipv6/netfilter/ip6t_REJECT.c

@@ -97,9 +97,11 @@ static void send_reset(struct net *net, struct sk_buff *oldskb)
 	fl.fl_ip_dport = otcph.source;
 	security_skb_classify_flow(oldskb, &fl);
 	dst = ip6_route_output(net, NULL, &fl);
-	if (dst == NULL)
+	if (dst == NULL || dst->error) {
+		dst_release(dst);
 		return;
-	if (dst->error || xfrm_lookup(net, &dst, &fl, NULL, 0))
+	}
+	if (xfrm_lookup(net, &dst, &fl, NULL, 0))
 		return;
 
 	hh_len = (dst->dev->hard_header_len + 15)&~15;