[gnome-boxes] vm-configurator: Handle "no cpu" case gracefully

[Zeeshan Ali Khattak <zeeshanak src gnome org>]

commit a6970ac521e783e142ff4a294d7c828380a0bdbf
Author: Christophe Fergeau <cfergeau redhat com>
Date:   Mon Mar 23 16:55:03 2015 +0100

    vm-configurator: Handle "no cpu" case gracefully
    
    A domain config can contain no CPU node (for example if it was removed
    using virsh edit). Such a domain triggers a warning on Boxes startup:
    
    (gnome-boxes:15373): Libvirt.GConfig-CRITICAL **: gvir_config_domain_cpu_get_mode: assertion 
'GVIR_CONFIG_IS_DOMAIN_CPU(cpu)' failed
    
    This commit makes sure we got a non-null GVirConfigDomainCpu before
    attempting to call get_mode() on it.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=746656

 src/vm-configurator.vala |    7 ++++---
 1 files changed, 4 insertions(+), 3 deletions(-)
---
diff --git a/src/vm-configurator.vala b/src/vm-configurator.vala
index 2b42a6c..f3978c5 100644
--- a/src/vm-configurator.vala
+++ b/src/vm-configurator.vala
@@ -234,9 +234,10 @@ private class Boxes.VMConfigurator {
     public static async void update_existing_domain (Domain          domain,
                                                      GVir.Connection connection) {
         try {
-            var mode = domain.get_cpu ().get_mode ();
-            if ((mode == DomainCpuMode.HOST_PASSTHROUGH ||
-                 mode == DomainCpuMode.HOST_MODEL) &&
+            var cpu = domain.get_cpu ();
+            if (cpu != null &&
+                (cpu.get_mode () == DomainCpuMode.HOST_PASSTHROUGH ||
+                 cpu.get_mode() == DomainCpuMode.HOST_MODEL) &&
                 is_boxes_installed (domain)) {
                 var capabilities = yield connection.get_capabilities_async (null);
                 set_cpu_config (domain, capabilities);