Several fixes and tweaks

This PR consists of:

* bogus change of using xml_location_t typedef
* new functions returning policy doc location
* FSM fixes, correcting crash and making nanny tolerate <client-info> and <client-state>
* ifdown attempts to delete Factory created devices, while leaves untouched physical ones
* Dropping of state-*.xml files for Factory created devices on deviceDelete()

Please review and TEST... I have been still testing it, so any help much appreciated.