netfilter: nft_meta: set skb->nf_trace appropriately

When user add a nft rule to set nftrace to zero, for example:

  # nft add rule ip filter input nftrace set 0

We should set nf_trace to zero also.
Signed-off-by: Liping Zhang <liping.zhang@spreadtrum.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

net/netfilter/nft_meta.c

@@ -227,7 +227,7 @@ void nft_meta_set_eval(const struct nft_expr *expr,
 			skb->pkt_type = value;
 		break;
 	case NFT_META_NFTRACE:
-		skb->nf_trace = 1;
+		skb->nf_trace = !!value;
 		break;
 	default:
 		WARN_ON(1);