[gnome-shell] slider: fix wrong variable name for own actor

[Alejandro Piñeiro Iglesias <apinheiro src gnome org>]

commit 3d57fd3227a192dbfbf83f71853cb9eb1ba118c4
Author: Alejandro Piñeiro <apinheiro igalia com>
Date:   Thu Aug 22 12:04:40 2013 +0200

    slider: fix wrong variable name for own actor
    
    https://bugzilla.gnome.org/show_bug.cgi?id=706386

 js/ui/slider.js |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/js/ui/slider.js b/js/ui/slider.js
index 025f0db..6005d3d 100644
--- a/js/ui/slider.js
+++ b/js/ui/slider.js
@@ -173,7 +173,7 @@ const Slider = new Lang.Class({
         if (key == Clutter.KEY_Right || key == Clutter.KEY_Left) {
             let delta = key == Clutter.KEY_Right ? 0.1 : -0.1;
             this._value = Math.max(0, Math.min(this._value + delta, 1));
-            this._slider.queue_repaint();
+            this.actor.queue_repaint();
             this.emit('value-changed', this._value);
             this.emit('drag-end');
             return true;