pvgrub: few lines in shutdown_blkfront were removed by mistake.

Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>

extras/mini-os/blkfront.c

@@ -244,6 +244,10 @@ void shutdown_blkfront(struct blkfront_dev *dev)
     xenbus_wait_for_value(path, "5", &dev->events);
 
     err = xenbus_printf(XBT_NIL, nodename, "state", "%u", 6);
+    xenbus_wait_for_value(path, "6", &dev->events);
+
+    err = xenbus_printf(XBT_NIL, nodename, "state", "%u", 1);
+    xenbus_wait_for_value(path, "2", &dev->events);
 
     xenbus_unwatch_path(XBT_NIL, path);