Fix positioning of panel on startup

We need to do the initial relayout before we start up the startup
animation, and the startup animation can't hardcode the position
of the panel to zero.

https://bugzilla.gnome.org/show_bug.cgi?id=642881

js/ui/main.js

@@ -196,6 +196,9 @@ function start() {
     ExtensionSystem.init();
     ExtensionSystem.loadExtensions();
 
+    // Perform initial relayout here
+    _relayout();
+
     panel.startStatusArea();
     panel.startupAnimation();
 
@@ -204,9 +207,6 @@ function start() {
 
     global.stage.connect('captured-event', _globalKeyPressHandler);
 
-    // Perform initial relayout here
-    _relayout();
-
     _log('info', 'loaded at ' + _startDate);
     log('GNOME Shell started at ' + _startDate);
 

js/ui/panel.js

@@ -1042,9 +1042,10 @@ Panel.prototype = {
     },
 
     startupAnimation: function() {
-        this.actor.y = -this.actor.height;
+        let oldY = this.actor.y;
+        this.actor.y = oldY - this.actor.height;
         Tweener.addTween(this.actor,
-                         { y: 0,
+                         { y: oldY,
                            time: 0.2,
                            transition: 'easeOutQuad'
                          });