[DCCP] ipv6: Fix opt_skb leak.

Based upon a patch from Jesper Juhl.  Try to match the
TCP IPv6 code this was copied from as much as possible,
so that it's easy to see where to add the ipv6 pktoptions
support code.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/dccp/ipv6.c

@@ -995,6 +995,10 @@ static int dccp_v6_do_rcv(struct sock *sk, struct sk_buff *skb)
 	if (sk->sk_state == DCCP_OPEN) { /* Fast path */
 		if (dccp_rcv_established(sk, skb, dccp_hdr(skb), skb->len))
 			goto reset;
+		if (opt_skb) {
+			/* This is where we would goto ipv6_pktoptions. */
+			__kfree_skb(opt_skb);
+		}
 		return 0;
 	}
 
@@ -1019,6 +1023,10 @@ static int dccp_v6_do_rcv(struct sock *sk, struct sk_buff *skb)
 
 	if (dccp_rcv_state_process(sk, skb, dccp_hdr(skb), skb->len))
 		goto reset;
+	if (opt_skb) {
+		/* This is where we would goto ipv6_pktoptions. */
+		__kfree_skb(opt_skb);
+	}
 	return 0;
 
 reset: