[NETFILTER]: nf_conntrack_netlink: fix unbalanced locking

Properly drop nf_conntrack_lock on tuple parsing error.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/netfilter/nf_conntrack_netlink.c

@@ -1237,7 +1237,7 @@ ctnetlink_new_conntrack(struct sock *ctnl, struct sk_buff *skb,
 						    CTA_TUPLE_MASTER,
 						    u3);
 			if (err < 0)
-				return err;
+				goto out_unlock;
 
 			master_h = __nf_conntrack_find(&master, NULL);
 			if (master_h == NULL) {