[gnome-boxes] Fix glib critical at the end of non-express installs

[Christophe Fergeau <teuf src gnome org>]

commit dcb1ed2b744d393bab9871bb73e43f4d330e4be7
Author: Christophe Fergeau <cfergeau redhat com>
Date:   Thu Jun 6 08:59:05 2013 +0200

    Fix glib critical at the end of non-express installs
    
    At the end of installations, regardless of if they are express
    installs or not, setup_post_install_domain_config is called.
    It unconditionally tries to remove 'disk_file' from the VM configuration.
    However, this member is only set for express installs, it's NULL
    for non-express installs, so we get glib criticals in the console
    when trying to use it as if it was non-NULL.
    This commit avoids this issue by checking if it's NULL before using
    it, as is done in most of unattended-installer.vala
    
    https://bugzilla.gnome.org/show_bug.cgi?id=701695

 src/unattended-installer.vala |    8 +++++---
 1 files changed, 5 insertions(+), 3 deletions(-)
---
diff --git a/src/unattended-installer.vala b/src/unattended-installer.vala
index 63d5158..f0ae6f6 100644
--- a/src/unattended-installer.vala
+++ b/src/unattended-installer.vala
@@ -272,10 +272,12 @@ private class Boxes.UnattendedInstaller: InstallerMedia {
     }
 
     public override void setup_post_install_domain_config (Domain domain) {
-        var path = disk_file.get_path ();
-        remove_disk_from_domain_config (domain, path);
+        if (disk_file != null) {
+            var path = disk_file.get_path ();
+            remove_disk_from_domain_config (domain, path);
+        }
         if (secondary_disk_file != null) {
-            path = secondary_disk_file.get_path ();
+            var path = secondary_disk_file.get_path ();
             remove_disk_from_domain_config (domain, path);
         }