[cheese] Fix keyboard shortcut window being displayed twice

[David King <davidk src gnome org>]

commit 9ae0bce4bdf076d37dd1f25e6cca5a435f3351c4
Author: Marcos José Brusso <mjbrusso gmail com>
Date:   Mon Apr 6 10:25:15 2020 -0300

    Fix keyboard shortcut window being displayed twice
    
    https://gitlab.gnome.org/GNOME/cheese/-/issues/57

 src/cheese-application.vala | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/src/cheese-application.vala b/src/cheese-application.vala
index f46f3165..d14571cf 100644
--- a/src/cheese-application.vala
+++ b/src/cheese-application.vala
@@ -490,7 +490,7 @@ public class Cheese.Application : Gtk.Application
             }
 
             shortcuts_window = builder.get_object ("shortcuts-cheese") as Gtk.ShortcutsWindow;
-            shortcuts_window.close.connect ( (event) => { shortcuts_window = null; } );
+            shortcuts_window.destroy.connect ( (event) => { shortcuts_window = null; } );
         }
 
         if (get_active_window () != shortcuts_window.get_transient_for ())