[IPV6]: Build fix and dst entry leak in neighbour discovery.

- NPRINTK2 will not compile if ND_DEBUG set to 3
- Missing dst_release in ndisc_send_rs if skb allocation fails.

net/ipv6/ndisc.c

@@ -207,9 +207,8 @@ static struct ndisc_options *ndisc_parse_options(u8 *opt, int opt_len,
 		case ND_OPT_MTU:
 		case ND_OPT_REDIRECT_HDR:
 			if (ndopts->nd_opt_array[nd_opt->nd_opt_type]) {
-				ND_PRINTK2((KERN_WARNING
-					    "ndisc_parse_options(): duplicated ND6 option found: type=%d\n",
-					    nd_opt->nd_opt_type));
+				ND_PRINTK2("ndisc_parse_options(): duplicated ND6 option found: type=%d\n",
+					    nd_opt->nd_opt_type);
 			} else {
 				ndopts->nd_opt_array[nd_opt->nd_opt_type] = nd_opt;
 			}
@@ -619,6 +618,7 @@ void ndisc_send_rs(struct net_device *dev, struct in6_addr *saddr,
 				  1, &err);
 	if (skb == NULL) {
 		ND_PRINTK1("send_ns: alloc skb failed\n");
+		dst_release(dst);
 		return;
 	}