Comment 28 for bug 1649527

On testing the Newton commit, I'm seeing the issue described here: https://bugs.launchpad.net/ubuntu/+source/libvirt/+bug/1665698

Based on the wording of https://en.wikibooks.org/wiki/QEMU/Networking, I think by removing the <script path=''/>, qemu is reverting to a default of trying to run '/etc/qemu-ifup', which is not allowed by the Ubuntu apparmor shipped with libvirt.