[gnome-panel] clock: fix warning

[Alberts Muktupāvels <muktupavels src gnome org>]

commit 66c7d68071bd652adbe9f3cb8ef0be8b38720867
Author: Alberts Muktupāvels <alberts muktupavels gmail com>
Date:   Sat Apr 16 22:15:00 2016 +0300

    clock: fix warning

 applets/clock/calendar-window.c |    8 ++++++--
 1 files changed, 6 insertions(+), 2 deletions(-)
---
diff --git a/applets/clock/calendar-window.c b/applets/clock/calendar-window.c
index c562c82..8914f48 100644
--- a/applets/clock/calendar-window.c
+++ b/applets/clock/calendar-window.c
@@ -1731,7 +1731,11 @@ calendar_window_dispose (GObject *object)
 static void
 calendar_window_class_init (CalendarWindowClass *klass)
 {
-       GObjectClass   *gobject_class   = G_OBJECT_CLASS (klass);
+       GObjectClass *gobject_class;
+       GtkWidgetClass *widget_class;
+
+       gobject_class = G_OBJECT_CLASS (klass);
+       widget_class = GTK_WIDGET_CLASS (klass);
 
        gobject_class->constructor = calendar_window_constructor;
        gobject_class->get_property = calendar_window_get_property;
@@ -1785,7 +1789,7 @@ calendar_window_class_init (CalendarWindowClass *klass)
                                      FALSE,
                                      G_PARAM_READWRITE | G_PARAM_CONSTRUCT));
 
-       gtk_widget_class_set_css_name (gobject_class, "gp-calendar-window");
+       gtk_widget_class_set_css_name (widget_class, "gp-calendar-window");
 }
 
 static void