[gnome-control-center] datetime: Don't use gtk_widget_show_all

[Georges Basile Stavracas Neto <gbsneto src gnome org>]

commit 6ce1a1dce68e98efa88e16c8b122470bf67df4d0
Author: Robert Ancell <robert ancell canonical com>
Date:   Mon Oct 1 15:29:33 2018 +1300

    datetime: Don't use gtk_widget_show_all
    
    It is removed in GTK+ 4

 panels/datetime/cc-datetime-panel.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)
---
diff --git a/panels/datetime/cc-datetime-panel.c b/panels/datetime/cc-datetime-panel.c
index 238cb2146..593815288 100644
--- a/panels/datetime/cc-datetime-panel.c
+++ b/panels/datetime/cc-datetime-panel.c
@@ -1023,13 +1023,14 @@ setup_am_pm_button (CcDateTimePanel *self)
 
   am_text = format_am_label ();
   self->am_label = gtk_label_new (am_text);
+  gtk_widget_show (self->am_label);
 
   pm_text = format_pm_label ();
   self->pm_label = gtk_label_new (pm_text);
+  gtk_widget_show (self->pm_label);
 
   gtk_container_add (GTK_CONTAINER (self->am_pm_stack), self->am_label);
   gtk_container_add (GTK_CONTAINER (self->am_pm_stack), self->pm_label);
-  gtk_widget_show_all (self->am_pm_stack);
   am_pm_stack_visible_child_changed_cb (self);
 
   provider = gtk_css_provider_new ();