Comment # 1 on bug 998343 from James Fehlig

See also the corresponding RH bug

https://bugzilla.redhat.com/show_bug.cgi?id=1342999

ATM, it is not clear whether this will be fixed in qemu or libvirt, or perhaps
even management apps like virt-manager. E.g. virt-manager could be changed to
not add a 'cache=' attribute to cdrom devices.

We might as well wait for a few days and see if there is a resolution
acceptable to the relevant upstream communities. In the meantime, 'virsh edit
domname' can be used to remove the 'cache=' attribute from empty cdrom devices.

BTW, I would be surprised if this bug doesn't exist in SLE12 SP2 as well.