[gnome-boxes] Fix disconnecting of display

[Marc-Andre Lureau <malureau src gnome org>]

commit 0f560dc52d618481d8df1d3238145a81906e962e
Author: Marc-Andrà Lureau <marcandre lureau gmail com>
Date:   Fri Nov 18 14:47:13 2011 +0100

    Fix disconnecting of display
    
    I introduced a regression with 8ef80d81b0bad3754db65505504c3fcdc80911c5

 src/libvirt-machine.vala |    4 +---
 1 files changed, 1 insertions(+), 3 deletions(-)
---
diff --git a/src/libvirt-machine.vala b/src/libvirt-machine.vala
index 2c51134..dfac8a2 100644
--- a/src/libvirt-machine.vala
+++ b/src/libvirt-machine.vala
@@ -21,7 +21,7 @@ private class Boxes.LibvirtMachine: Boxes.Machine {
 
         _connect_display = false;
         app.display_page.remove_display ();
-        update_display ();
+        display = null;
     }
 
     private ulong started_id;
@@ -249,8 +249,6 @@ private class Boxes.LibvirtMachine: Boxes.Machine {
     private void update_display () {
         string type, port, socket, host;
 
-        // TODO: this assertion holds true for the moment, I don't see
-        // yet why it shouldn't be
         return_if_fail (_connect_display == true);
 
         try {