nft: fix leak of chain iterator in nft_rule_list

Signed-off-by: Giuseppe Longo <giuseppelng@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
diff --git a/iptables/nft.c b/iptables/nft.c
index 6a4898d..1c7c75e 100644
--- a/iptables/nft.c
+++ b/iptables/nft.c
@@ -2524,6 +2524,7 @@
 		c = nft_chain_list_iter_next(iter);
 	}
 
+	nft_chain_list_iter_destroy(iter);
 	nft_chain_list_free(list);
 
 	return 1;