When building cloud images oz uses dracut to setup networking and it
    in turn makes a ifcfg-en<something> file with this config. We don't
    want to use this, we want to always use ifcfg-eth0 so it's the same
    on all images. So, we remove ifcfg-en* (They are different on each
    arch we make cloud images for, but en* gets them all).
    Additionally we were using some old udev tricks to get eth0, but this
    is error prone and already incorrect as systemd-udev has moved files
    around, so instead we just switch to net.ifnames=0 on the boot line,
    which should continue working.