[gnome-boxes] app-window: Disconnect Machine.deleted notify

[Zeeshan Ali <zeeshanak src gnome org>]

commit 547ce0a32e2ba5175efe9b0c1f46e8db42632553
Author: Visarion Alexandru <viorel visarion gmail com>
Date:   Mon Jul 4 11:28:43 2016 +0300

    app-window: Disconnect Machine.deleted notify
    
    The problem is that currently a window will listen to notifications
    from a machine long after it has been replaced with another machine.
    This leads to unpredictable behaviour, like windows being removed
    because one of its previous machines has been deleted.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=767214

 src/app-window.vala |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)
---
diff --git a/src/app-window.vala b/src/app-window.vala
index 7622fec..e3b7144 100644
--- a/src/app-window.vala
+++ b/src/app-window.vala
@@ -24,6 +24,7 @@ private class Boxes.AppWindow: Gtk.ApplicationWindow, Boxes.UI {
         set {
             if (_current_item != null) {
                 _current_item.disconnect (machine_state_notify_id);
+                _current_item.disconnect (machine_deleted_notify_id);
                 machine_state_notify_id = 0;
                 machine_deleted_notify_id = 0;
             }