We want to make sure people who have both pinned and unpinned instances
on a host (yes, it's dumb, but it happens) won't do a straightforward
'vcpu_pin_set' -> '[compute] cpu_dedicated_set' or '[compute]
cpu_shared_set' transition, breaking their ability to restart or rebuild
instances. We add a new 'supports_pcpus' driver capability to avoid
needing to do this on drivers that don't support PCPUs and CPU pinning
in general.
Change-Id: Ia1b3ab0b66fdaf569f6c7a09510f208ee28725b2
Signed-off-by: Stephen Finucane <sfinucan@redhat.com>