Designer: Remove unnecessary connect

It also connects to a signal that will be removed soon.

Change-Id: Ib5bbfb3d72d08280317069068d71ed08e5159d8f
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@digia.com>
Reviewed-by: Jarek Kobus <jaroslaw.kobus@digia.com>
Reviewed-by: Eike Ziller <eike.ziller@digia.com>