Comment 22 for bug 1718668

Discussion ended in a suggested fix in [1].
Builds are fine on all arches now [2], given the changes I'm running a shorter set of regression checks to be sure (no test would be too few, but no need for ALL on all-arch given an this is an optarg change).

Will update here and upload after tests are (hopefully) good.

[1]: https://www.redhat.com/archives/libvir-list/2017-October/msg00331.html
[2]: https://launchpad.net/~ci-train-ppa-service/+archive/ubuntu/2987/+packages