[gnome-shell/eos3.8: 142/255] unlockDialog: Only cancel auth prompt if object exists

[Matthew Leeds <mwleeds src gnome org>]

commit acb24a8ce835ecc851b333ff8696fa1743d463c5
Author: Andre Moreira Magalhaes <andre endlessm com>
Date:   Fri Mar 27 11:47:41 2020 -0300

    unlockDialog: Only cancel auth prompt if object exists
    
    This fixes the following exception:
      JS ERROR: TypeError: this._authPrompt is undefined
      _escape@resource:///org/gnome/shell/ui/unlockDialog.js:765:13
    
    https://phabricator.endlessm.com/T28780

 js/ui/unlockDialog.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/js/ui/unlockDialog.js b/js/ui/unlockDialog.js
index d27b1d59ca..2170f12a76 100644
--- a/js/ui/unlockDialog.js
+++ b/js/ui/unlockDialog.js
@@ -761,7 +761,7 @@ var UnlockDialog = GObject.registerClass({
     }
 
     _escape() {
-        if (this.allowCancel)
+        if (this._authPrompt && this.allowCancel)
             this._authPrompt.cancel();
     }