[gnome-boxes] wizard: Make back button sensitive after page change

[Zeeshan Ali Khattak <zeeshanak src gnome org>]

commit 09a948843fcd2d55ecee2d43c51b2ba0e3fb3948
Author: Radu Stochitoiu <radu stochitoiu gmail com>
Date:   Tue May 24 21:05:50 2016 +0300

    wizard: Make back button sensitive after page change
    
    Back button sensitivity is currently updated before page change is
    successful, making the button sensitive on the 'source' page after an
    unsuccessful switch to 'preparation' page. Fix this by setting the back
    button sensitivity after the page change is successful.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=753172

 src/wizard.vala |    3 +--
 1 files changed, 1 insertions(+), 2 deletions(-)
---
diff --git a/src/wizard.vala b/src/wizard.vala
index dbfe062..f715eab 100644
--- a/src/wizard.vala
+++ b/src/wizard.vala
@@ -61,8 +61,6 @@ private class Boxes.Wizard: Gtk.Stack, Boxes.UI {
     public WizardPage page {
         get { return _page; }
         set {
-            back_button.sensitive = (value != WizardPage.SOURCE);
-
             var forwards = value > page;
 
             switch (value) {
@@ -134,6 +132,7 @@ private class Boxes.Wizard: Gtk.Stack, Boxes.UI {
                 return;
 
             _page = value;
+            back_button.sensitive = (value != WizardPage.SOURCE);
             wizard_window.topbar.set_title_for_page (value);
             visible_child_name = page_names[value];