Revert "Defer initializing UI until after the global session has loaded"

This reverts commit 0bef925b51.

Just for now.  Jasper has plans to clean up start up eventually.

https://bugzilla.gnome.org/show_bug.cgi?id=694321

js/ui/main.js

@@ -98,21 +98,19 @@ function start() {
 
     Gio.DesktopAppInfo.set_desktop_env('GNOME');
 
+    sessionMode = new SessionMode.SessionMode();
+
+    // start session after we know what mode we're running in
+    let signalId = sessionMode.connect('updated', function() {
+                                           sessionMode.disconnect(signalId);
+                                           startSession();
+                                       });
+}
+
+function startSession() {
     shellDBusService = new ShellDBus.GnomeShell();
     shellMountOpDBusService = new ShellMountOperation.GnomeShellMountOpHandler();
 
-    sessionMode = new SessionMode.SessionMode();
-    sessionMode.connect('sessions-loaded', _sessionsLoaded);
-    sessionMode.init();
-}
-
-function _sessionsLoaded() {
-    sessionMode.connect('updated', _sessionUpdated);
-    _initializeUI();
-    _sessionUpdated();
-}
-
-function _initializeUI() {
     // Ensure ShellWindowTracker and ShellAppUsage are initialized; this will
     // also initialize ShellAppSystem first.  ShellAppSystem
     // needs to load all the .desktop files, and ShellWindowTracker