[Libosinfo] Really enable QXL

[Zeeshan Ali (Khattak)]

These patches are required to actually enable QXL in Windows XP and 7. They have already been through many iterations and I kinda lost track of versions so sending them as new patches. Hope thats acceptable. Please find more details about each patch in it's commit log.

Apps (e.g Boxes) will have to adapt to these changes if they want virtio/QXL drivers to be automatically installed on new VMs. Its not really a problem since one of the most essential driver, QXL was not working anyways.