drbd: switch to proc_create_single

And stop messing with try_module_get on THIS_MODULE, which doesn't make
any sense here.

Signed-off-by: Christoph Hellwig <hch@lst.de>

drivers/block/drbd/drbd_main.c

@@ -3010,7 +3010,8 @@ static int __init drbd_init(void)
 		goto fail;
 
 	err = -ENOMEM;
-	drbd_proc = proc_create_data("drbd", S_IFREG | S_IRUGO , NULL, &drbd_proc_fops, NULL);
+	drbd_proc = proc_create_single("drbd", S_IFREG | S_IRUGO , NULL,
+			drbd_seq_show);
 	if (!drbd_proc)	{
 		pr_err("unable to register proc file\n");
 		goto fail;