alternative-status-menu: disconnect signals for IMStatusChooserItem

In master shell, calling destroy does this automatically, but the
patch was not backported, so we need to hack around this here.

extensions/alternative-status-menu/extension.js

@@ -124,7 +124,14 @@ function enable() {
 function disable() {
     // not guarranteed to work, if more extensions operate in the same place
     let statusMenu = Main.panel._statusArea.userMenu;
+
+    // HACK! disconnect signals to avoid references to destroyed objects
+    let imstatusitem = statusMenu.menu._getMenuItems()[0];
+    imstatusitem._user.disconnect(imstatusitem._userLoadedId);
+    imstatusitem._user.disconnect(imstatusitem._userChangedId);
+
     statusMenu.menu.removeAll();
+
     statusMenu._createSubMenu();
     reset(statusMenu);
 }