[gnome-boxes] wizard: Only update wizard source on SOURCE page

[Zeeshan Ali Khattak <zeeshanak src gnome org>]

commit 58bb18a328c2f3db3c3b656edcc8bd93630a2084
Author: Zeeshan Ali (Khattak) <zeeshanak gnome org>
Date:   Sun Feb 23 15:47:31 2014 +0000

    wizard: Only update wizard source on SOURCE page
    
    This fixes the issue of 'Continue' button getting insensitive on
    cancelling the wizard at INTRODUCTION page.

 src/wizard.vala |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)
---
diff --git a/src/wizard.vala b/src/wizard.vala
index 29c8ec3..89b6c34 100644
--- a/src/wizard.vala
+++ b/src/wizard.vala
@@ -130,6 +130,9 @@ private class Boxes.Wizard: Gtk.Notebook, Boxes.UI {
     }
 
     private void wizard_source_update_next () {
+        if (page != WizardPage.SOURCE)
+            return;
+
         next_button.sensitive = false;
 
         switch (wizard_source.page) {