netfilter: x_tables: fix net namespace leak when reading /proc/net/xxx_tables_names

The seq_open_net() call should be accompanied with seq_release_net() one.
Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/netfilter/x_tables.c

@@ -787,7 +787,7 @@ static const struct file_operations xt_table_ops = {
 	.open	 = xt_table_open,
 	.read	 = seq_read,
 	.llseek	 = seq_lseek,
-	.release = seq_release,
+	.release = seq_release_net,
 };
 
 static void *xt_match_seq_start(struct seq_file *seq, loff_t *pos)