[gnome-shell] panel: Remove this.actor definition to self

[Florian Müllner <fmuellner src gnome org>]

commit be2d630348c68be2ca79c24a25a712c438256904
Author: Marco Trevisan (Treviño) <mail 3v1n0 net>
Date:   Tue Apr 9 18:25:41 2019 -0500

    panel: Remove this.actor definition to self
    
    Remove this.actor = actor, since the class is now an actor itself.
    
    https://gitlab.gnome.org/GNOME/gnome-shell/merge_requests/487

 js/ui/panel.js | 3 ---
 1 file changed, 3 deletions(-)
---
diff --git a/js/ui/panel.js b/js/ui/panel.js
index ec6ae1537..9790d4843 100644
--- a/js/ui/panel.js
+++ b/js/ui/panel.js
@@ -825,9 +825,6 @@ class Panel extends St.Widget {
         super._init({ name: 'panel',
                       reactive: true });
 
-        // For compatibility with extensions that still use the
-        // this.actor field
-        this.actor = this;
         this.set_offscreen_redirect(Clutter.OffscreenRedirect.ALWAYS);
 
         this._sessionStyle = null;