[gnome-control-center] printers: Drop unused class structure

[Robert Ancell <rancell src gnome org>]

commit a50ce396896b65a1c1e00ed7252dc9d8d780a313
Author: Robert Ancell <robert ancell canonical com>
Date:   Fri Nov 23 13:45:19 2018 +1300

    printers: Drop unused class structure

 panels/printers/pp-details-dialog.c | 7 -------
 1 file changed, 7 deletions(-)
---
diff --git a/panels/printers/pp-details-dialog.c b/panels/printers/pp-details-dialog.c
index abf20cb01..dcfdf7922 100644
--- a/panels/printers/pp-details-dialog.c
+++ b/panels/printers/pp-details-dialog.c
@@ -60,13 +60,6 @@ struct _PpDetailsDialog {
   PpPPDSelectionDialog *pp_ppd_selection_dialog;
 };
 
-struct _PpDetailsDialogClass
-{
-  GtkDialogClass parent_class;
-
-  void (*printer_renamed) (PpDetailsDialog *details_dialog, const gchar *new_name);
-};
-
 G_DEFINE_TYPE (PpDetailsDialog, pp_details_dialog, GTK_TYPE_DIALOG)
 
 enum