[gnome-shell-extensions] apps-menu: Remove more dead code

[Florian Müllner <fmuellner src gnome org>]

commit 69700dc29b20f01d6ea00636c163e90ab7e00ffd
Author: Alexander Rüedlinger <a rueedlinger gmail com>
Date:   Fri Jul 21 02:57:37 2017 +0200

    apps-menu: Remove more dead code
    
    Commit 0a91893b02a removed dead code, namely a ::panel-box-changed signal
    handler. Unfortunately, it forgot to remove the associated code that
    disconnects the signal.
    
    Signed-off-by: Alexander Rüedlinger <a rueedlinger gmail com>
    
    https://bugzilla.gnome.org/show_bug.cgi?id=785202

 extensions/apps-menu/extension.js |    1 -
 1 files changed, 0 insertions(+), 1 deletions(-)
---
diff --git a/extensions/apps-menu/extension.js b/extensions/apps-menu/extension.js
index 9429534..8668b59 100644
--- a/extensions/apps-menu/extension.js
+++ b/extensions/apps-menu/extension.js
@@ -494,7 +494,6 @@ const ApplicationsButton = new Lang.Class({
     _onDestroy: function() {
         Main.overview.disconnect(this._showingId);
         Main.overview.disconnect(this._hidingId);
-        Main.layoutManager.disconnect(this._panelBoxChangedId);
         appSys.disconnect(this._installedChangedId);
 
         Main.wm.setCustomKeybindingHandler('panel-main-menu',