In the past we updated host-model CPUs with host CPU data by adding a
model and features, but keeping the host-model mode. And since the CPU
model is not normally formatted for host-model CPU defs, we had to pass
the updateCPU flag to the formatting code to be able to properly output
updated host-model CPUs. Libvirt doesn't do this anymore, host-model
CPUs are turned into custom mode CPUs once updated with host CPU data
and thus there's no reason for keeping the hacks inside CPU XML
formatters.
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>