Comment # 20 on bug 987668 from James Fehlig

Patch committed upstream after a small tweak to address review comments. I've
added the patch to the libvirt package in Virtualization and forwarded it to
Factory/Tumbleweed (SR#407950). I also added the patch to the SLE12 SP2 libvirt
package, even though we haven't seen the problem with systemd v228.