[gnome-shell] batch: Add missing import

[Georges Basile Stavracas Neto <gbsneto src gnome org>]

commit a8f0787c91a9fd037e212286359ab72ceed34f3d
Author: Florian Müllner <fmuellner gnome org>
Date:   Sat Jun 29 14:18:34 2019 +0200

    batch: Add missing import
    
    Commit 88697add1b55c missed adding the necessary import.
    
    Spotted by eslint.
    
    https://gitlab.gnome.org/GNOME/gnome-shell/merge_requests/606

 js/gdm/batch.js | 1 +
 1 file changed, 1 insertion(+)
---
diff --git a/js/gdm/batch.js b/js/gdm/batch.js
index 3671210e0..3b7852f7e 100644
--- a/js/gdm/batch.js
+++ b/js/gdm/batch.js
@@ -44,6 +44,7 @@
  * replaced by something else.
  */
 
+const { GObject } = imports.gi;
 const Signals = imports.signals;
 
 var Task = class {