Domains configured with autostart may fail to start if the host
network stack has not been started.  E.g. when using bridged
networking autostarting a domain can fail with

libvirtd[1403]: 2012-06-20 13:23:49.833+0000: 1485: error :
qemuAutostartDomain:177 : Failed to autostart VM 'test': Cannot get
interface MTU on 'br0': No such device
(cherry picked from commit 4036aa91)