[gnome-control-center] network: Fix warning on panel exit

[Bastien Nocera <hadess src gnome org>]

commit ba6da7636ef2135586475784120aa7b5cd50e71c
Author: Bastien Nocera <hadess hadess net>
Date:   Wed Mar 18 18:15:35 2015 +0100

    network: Fix warning on panel exit
    
    Now that the VPN object is getting finalized, make sure not to warn if
    the NMClient is already gone.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=746411

 panels/network/net-vpn.c |    8 +++++---
 1 files changed, 5 insertions(+), 3 deletions(-)
---
diff --git a/panels/network/net-vpn.c b/panels/network/net-vpn.c
index 98acb2c..c6fdda1 100644
--- a/panels/network/net-vpn.c
+++ b/panels/network/net-vpn.c
@@ -503,9 +503,11 @@ net_vpn_finalize (GObject *object)
         NetVpnPrivate *priv = vpn->priv;
         NMClient *client = net_object_get_client (NET_OBJECT (object));
 
-        g_signal_handlers_disconnect_by_func (client,
-                                              nm_active_connections_changed,
-                                              vpn);
+        if (client) {
+                g_signal_handlers_disconnect_by_func (client,
+                                                      nm_active_connections_changed,
+                                                      vpn);
+        }
 
         if (priv->active_connection) {
                 g_signal_handlers_disconnect_by_func (priv->active_connection,