Fix builing of qml2puppet on windows

Make sure trailing c: is stripped from path

Change-Id: Ie641b7e2f8e556ce8b110103ac98d0161b16e8d3
Reviewed-by: Eike Ziller <eike.ziller@digia.com>
Reviewed-by: Kai Koehne <kai.koehne@digia.com>