alternative-status-menu: disconnect signals on enable() too

We need to disconnect the signals every time we destroy the
IMStatusChooserItem, that is, both at enable() and at disable().

(In particular, disconnecting at disable() doesn't matter much, since
those signals are emitted only very early after login - which is why
enabling in the middle of session worked before)

extensions/alternative-status-menu/extension.js

@@ -103,6 +103,13 @@ function init(metadata) {
     imports.gettext.bindtextdomain('gnome-shell-extensions', GLib.build_filenamev([metadata.path, 'locale']));
 }
 
+function predestroy(statusMenu) {
+    // 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);
+}
+
 function reset(statusMenu) {
     statusMenu._updateSwitchUser();
     statusMenu._updateLogout();
@@ -116,7 +123,10 @@ function reset(statusMenu) {
 
 function enable() {
     let statusMenu = Main.panel._statusArea.userMenu;
+
+    predestroy(statusMenu);
     statusMenu.menu.removeAll();
+
     createSubMenu.call(statusMenu);
     reset(statusMenu);
 }
@@ -125,11 +135,7 @@ 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);
-
+    predestroy(statusMenu);
     statusMenu.menu.removeAll();
 
     statusMenu._createSubMenu();