[gnome-shell] appDisplay: Don't call a non-existent onComplete

[Rui Matos <rtcm src gnome org>]

commit 4ff489d24b4ee3b72615d0b938dca429db77c9cc
Author: Rui Matos <tiagomatos gmail com>
Date:   Wed Mar 4 18:58:14 2015 +0100

    appDisplay: Don't call a non-existent onComplete
    
    Follow up to commit 6bb905895c932db51ff0314fecec765f2f703f31 .
    
    https://bugzilla.gnome.org/show_bug.cgi?id=745627

 js/ui/appDisplay.js |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)
---
diff --git a/js/ui/appDisplay.js b/js/ui/appDisplay.js
index e1ff13a..f835946 100644
--- a/js/ui/appDisplay.js
+++ b/js/ui/appDisplay.js
@@ -544,7 +544,8 @@ const AllView = new Lang.Class({
         this._scrollView.reactive = false;
         let completionFunc = Lang.bind(this, function() {
             this._scrollView.reactive = true;
-            onComplete();
+            if (onComplete)
+                onComplete();
         });
 
         if (animationDirection == IconGrid.AnimationDirection.OUT &&