[gnome-shell] loginDialog: Stop using deprecated actor property

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

commit 7b45ffa511bf8fe12e80e937729e23345f51f89a
Author: Florian Müllner <fmuellner gnome org>
Date:   Fri Sep 20 13:09:13 2019 +0200

    loginDialog: Stop using deprecated actor property
    
    Commit 0c0d76f7d6990 made the class an actor subclass, so the actor
    property is just a deprecated synonym of the object itself.
    
    https://gitlab.gnome.org/GNOME/gnome-shell/merge_requests/736

 js/gdm/loginDialog.js | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/js/gdm/loginDialog.js b/js/gdm/loginDialog.js
index 76edcf44f3..c3f90dc584 100644
--- a/js/gdm/loginDialog.js
+++ b/js/gdm/loginDialog.js
@@ -921,7 +921,7 @@ var LoginDialog = GObject.registerClass({
             return;
 
         this._bindOpacity();
-        this.actor.ease({
+        this.ease({
             opacity: 255,
             duration: _FADE_ANIMATION_TIME,
             mode: Clutter.AnimationMode.EASE_OUT_QUAD,
@@ -944,7 +944,7 @@ var LoginDialog = GObject.registerClass({
 
     _startSession(serviceName) {
         this._bindOpacity();
-        this.actor.ease({
+        this.ease({
             opacity: 0,
             duration: _FADE_ANIMATION_TIME,
             mode: Clutter.AnimationMode.EASE_OUT_QUAD,