[gnome-control-center] background: Update clock in both preview modes

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

commit ecd27846f85a532ca4fe83dfaad83e3bfe47ca14
Author: Philip Chimento <philip endlessm com>
Date:   Tue Sep 24 12:50:32 2019 -0700

    background: Update clock in both preview modes
    
    There is a clock widget both on the desktop preview and the lock screen.
    Without this change, the clock on the desktop preview is always blank.

 panels/background/cc-background-preview.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)
---
diff --git a/panels/background/cc-background-preview.c b/panels/background/cc-background-preview.c
index a4fa31233..584ccca6b 100644
--- a/panels/background/cc-background-preview.c
+++ b/panels/background/cc-background-preview.c
@@ -232,10 +232,6 @@ cc_background_preview_set_property (GObject      *object,
       self->is_lock_screen = g_value_get_boolean (value);
       gtk_stack_set_visible_child_name (self->stack,
                                         self->is_lock_screen ? "lock" : "desktop");
-      if (self->is_lock_screen)
-        start_monitor_time (self);
-      else
-        stop_monitor_time (self);
       break;
 
     case PROP_ITEM:
@@ -351,6 +347,7 @@ cc_background_preview_init (CcBackgroundPreview *self)
 
   update_clock_format (self);
   load_custom_css (self);
+  start_monitor_time (self);
 }
 
 CcBackgroundItem*