[seahorse] sidebar: Add backend name to debug message

[Niels De Graef <nielsdg src gnome org>]

commit 65d1207445ff6b82f3926959a54a08eaa032a5fa
Author: Niels De Graef <nielsdegraef gmail com>
Date:   Sat Jun 20 15:18:19 2020 +0200

    sidebar: Add backend name to debug message

 src/sidebar.vala | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)
---
diff --git a/src/sidebar.vala b/src/sidebar.vala
index 098cf876..b991d006 100644
--- a/src/sidebar.vala
+++ b/src/sidebar.vala
@@ -91,7 +91,8 @@ public class Seahorse.Sidebar : Gtk.ListBox {
     }
 
     private void on_backend_changed(GLib.Object obj, ParamSpec spec) {
-        debug("Backend changed");
+        Backend backend = (Backend) obj;
+        debug("Backend '%s' changed", backend.label);
         update_places();
     }