Code review comment for ~agherzan/uvtool:ag/libvirtcon

FWIW, you probably noticed that the way this is done makes it painful to make the URI a configurable option. This diff reminded me that I thought about this when I wrote it. I imagined that I would need to add some kind of state object to carry user options and pass it around everywhere, to avoid a global variable. Maybe a class, or just a namedtuple or something. To get the initial version out the door I kicked that can down the road, and here we are many years later and you're the first person to notice :-)