Don't build scanner example without QtQuick

Task-number: QTBUG-35711
Change-Id: I0406fb5edd8fb2a90046308853485eaaa4311a26
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@digia.com>
Reviewed-by: Fabian Bumberger <fbumberger@rim.com>
Reviewed-by: Alex Blasche <alexander.blasche@digia.com>