[gnome-boxes] Fix warnings if canceling opening vm

[Alexander Larsson <alexl src gnome org>]

commit 3b04c1130c4d57aa55fd173f23396691e084e563
Author: Alexander Larsson <alexl redhat com>
Date:   Thu Jun 7 19:55:00 2012 +0200

    Fix warnings if canceling opening vm
    
    The timeout was triggering warnings if you clicked back fast enough.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=677274

 src/machine.vala |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)
---
diff --git a/src/machine.vala b/src/machine.vala
index 29ac004..b6b5fd4 100644
--- a/src/machine.vala
+++ b/src/machine.vala
@@ -59,6 +59,8 @@ private abstract class Boxes.Machine: Boxes.CollectionItem, Boxes.IPropertiesPro
             show_id = _display.show.connect ((id) => {
                 App.app.ui_state = Boxes.UIState.DISPLAY;
                 Timeout.add (App.app.duration, () => {
+                    if  (App.app.ui_state != Boxes.UIState.DISPLAY)
+                          return false;
                     try {
                         var widget = display.get_display (0);
                         App.app.display_page.show_display (display, widget);