rados: convert to common errno handling
rados: convert to common errno handling

Use the errno handling function originally created for rbd and
then made common in rados package.

Signed-off-by: John Mulligan <eda8ad33169deab44f9fe65847f99e368da6c91b@redhat.com>

ceph/go-ceph,ceph/go-ceph,ceph/go-ceph