[gnome-control-center] power: Avoid warning with no keyboard backlight

[Bastien Nocera <hadess src gnome org>]

commit f7c5225288b03c7a6f8139a1c02b840c7eddda8d
Author: Bastien Nocera <hadess hadess net>
Date:   Tue Aug 20 04:26:23 2013 +0200

    power: Avoid warning with no keyboard backlight
    
    If there's no keyboard backlight interface in gnome-settings-daemon,
    hide the slider as well, rather than throw a warning.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=706040

 panels/power/cc-power-panel.c |   14 ++++++++++----
 1 files changed, 10 insertions(+), 4 deletions(-)
---
diff --git a/panels/power/cc-power-panel.c b/panels/power/cc-power-panel.c
index 3d23e0b..f82044a 100644
--- a/panels/power/cc-power-panel.c
+++ b/panels/power/cc-power-panel.c
@@ -891,10 +891,16 @@ sync_kbd_brightness (CcPowerPanel *self)
   GtkRange *range;
 
   result = g_dbus_proxy_get_cached_property (self->priv->kbd_proxy, "Brightness");
-
-  /* set the slider */
-  g_variant_get (result, "i", &brightness);
-  visible = brightness >= 0.0;
+  if (result)
+    {
+      /* set the slider */
+      brightness = g_variant_get_uint32 (result);
+      visible = brightness >= 0.0;
+    }
+  else
+    {
+      visible = FALSE;
+    }
 
   gtk_widget_set_visible (self->priv->kbd_brightness_row, visible);