popupMenu: Hide settings menus outside user session

The control-center contains user-pertinent settings
panels. These panels don't make sense to show outside
of a user's session, so hide them for session types other
than SessionType.USER.

https://bugzilla.gnome.org/show_bug.cgi?id=657082

js/ui/dateMenu.js

@@ -97,13 +97,14 @@ DateMenuButton.prototype = {
         vbox.add(this._calendar.actor);
 
         item = this.menu.addSettingsAction(_("Date and Time Settings"), 'gnome-datetime-panel.desktop');
-
+        if (item) {
             let separator = new PopupMenu.PopupSeparatorMenuItem();
             separator.setColumnWidths(1);
             vbox.add(separator.actor, {y_align: St.Align.END, expand: true, y_fill: false});
 
             item.actor.can_focus = false;
             item.actor.reparent(vbox);
+        }
 
         if (params.showEvents) {
             // Add vertical separator

js/ui/popupMenu.js

@@ -813,6 +813,10 @@ PopupMenuBase.prototype = {
     },
 
     addSettingsAction: function(title, desktopFile) {
+        // Don't allow user settings to get edited unless we're in a user session
+        if (global.session_type != Shell.SessionType.USER)
+            return null;
+
         let menuItem = this.addAction(title, function() {
                            let app = Shell.AppSystem.get_default().lookup_setting(desktopFile);