Added task decorators. Fixed version ToDo item
Starting with libvirt 0.9.11, mdns_adv is already disabled
TODO: check whether libvirt <= 0.9.10, then avahi should get disabled
Moved libvirtd.conf patch within skeletton
upload_string(): only attempt to backup a file that already exists
More TODOs
Many many bugfixes of formerly untested install_libvirt_host()