Set correct dialog window hint for progress dialog (again) (bug #11467)

Except deprecated compiz every window manager tested so far works fine
with this. Reapplying again.

thunar/thunar-progress-dialog.c

@@ -96,7 +96,7 @@ thunar_progress_dialog_init (ThunarProgressDialog *dialog)
   gtk_window_set_modal (GTK_WINDOW (dialog), FALSE);
   gtk_window_set_transient_for (GTK_WINDOW (dialog), NULL);
   gtk_window_set_destroy_with_parent (GTK_WINDOW (dialog), FALSE);
-  gtk_window_set_type_hint (GTK_WINDOW (dialog), GDK_WINDOW_TYPE_HINT_NORMAL);
+  gtk_window_set_type_hint (GTK_WINDOW (dialog), GDK_WINDOW_TYPE_HINT_DIALOG);
 
   g_signal_connect_swapped (dialog, "show", 
                             G_CALLBACK (thunar_progress_dialog_shown), dialog);