netfilter: nft_ct: include direction when dumping NFT_CT_L3PROTOCOL key

one nft userspace test case fails with

'ct l3proto original ipv4' mismatches 'ct l3proto ipv4'

... because NFTA_CT_DIRECTION attr is missing.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

net/netfilter/nft_ct.c

@@ -366,6 +366,7 @@ static int nft_ct_get_dump(struct sk_buff *skb, const struct nft_expr *expr)
 		goto nla_put_failure;
 
 	switch (priv->key) {
+	case NFT_CT_L3PROTOCOL:
 	case NFT_CT_PROTOCOL:
 	case NFT_CT_SRC:
 	case NFT_CT_DST: