[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: David S. Miller <davem@davemloft.net>
diff --git a/net/dccp/ipv6.c b/net/dccp/ipv6.c
index 91e7b12..c8bf89b 100644
--- a/net/dccp/ipv6.c
+++ b/net/dccp/ipv6.c
@@ -995,6 +995,10 @@
 	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 @@
 
 	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: