[gnome-control-center] printers: Fix string leaks in new printer dialog

[Marek Kašík <mkasik src gnome org>]

commit 388e59e66aacb9a4ff50282b32e06d288c5d6d3e
Author: Robert Ancell <robert ancell canonical com>
Date:   Tue Nov 10 15:03:47 2020 +1300

    printers: Fix string leaks in new printer dialog

 panels/printers/pp-new-printer-dialog.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/panels/printers/pp-new-printer-dialog.c b/panels/printers/pp-new-printer-dialog.c
index bc3af4609..20c041416 100644
--- a/panels/printers/pp-new-printer-dialog.c
+++ b/panels/printers/pp-new-printer-dialog.c
@@ -1895,8 +1895,8 @@ ppd_selection_cb (GtkDialog *_dialog,
   PpNewPrinterDialog        *self = user_data;
   g_autoptr(PpNewPrinter)    new_printer = NULL;
   GList                     *original_names_list = NULL;
-  gchar                     *ppd_name;
-  gchar                     *ppd_display_name;
+  g_autofree gchar          *ppd_name = NULL;
+  g_autofree gchar          *ppd_display_name = NULL;
   guint                      window_id = 0;
   gint                       acquisition_method;