https://bugzilla.redhat.com/show_bug.cgi?id=1258361
When attaching a disk, controller, or rng using an address type ccw
or s390, we need to ensure the support is provided by both the machine.os
and the emulator capabilities (corollary to unconditional setting when
address was not provided for the correct machine.os and emulator.
For an inactive guest, an addition followed by a start would cause the
startup to fail after qemu_command builds the command line and attempts
to start the guest. For an active guest, libvirtd would crash.
a39ab90908