drbd: Remove headers from on-the-wire data structures (struct p_*)

Prepare the introduction of the protocol 100 headers. The actual protocol
header is removed for the packet declarations. I.e. allow us to use the
packets with different headers.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
diff --git a/drivers/block/drbd/drbd_worker.c b/drivers/block/drbd/drbd_worker.c
index 78b95e9..086a4b6 100644
--- a/drivers/block/drbd/drbd_worker.c
+++ b/drivers/block/drbd/drbd_worker.c
@@ -1229,7 +1229,7 @@
 	sock = &mdev->tconn->data;
 	if (!drbd_prepare_command(mdev, sock))
 		return -EIO;
-	return drbd_send_command(mdev, sock, P_UNPLUG_REMOTE, sizeof(struct p_header), NULL, 0);
+	return drbd_send_command(mdev, sock, P_UNPLUG_REMOTE, 0, NULL, 0);
 }
 
 int w_send_out_of_sync(struct drbd_work *w, int cancel)