[libvirt] libvirt-gconfig patches

[Christophe Fergeau]

Hi,

This is the 2nd version of my libvirt-gconfig patches. I think I have
addressed all of the issues that were raised (or told why I didn't address
them). If I missed anything, just let me know.
Some of the patches have been split/merged after the review so the series
look a bit different from the first one even if the content is the same.
One notable change is that I dropped the chardev classes for now since I
need to go back to the drawing board a bit for these

Christophe