The load_super() from an mdadm --detail call may race against an mdmon
update. When this happens the load_super sees an inconsistent metadata
block and returns an error. The fallback path to use the map file
contents lacks uuid reporting, so provide __fname_from_uuid for
generically printing a uuid.
Reported-by: Hans de Goede <hdegoede@redhat.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>