Comment 0 for bug 1808089

In microversion 2.20 we added the ablility to detach/attach volumes from a shelved(_offloaded) instance:
http://git.openstack.org/cgit/openstack/nova/tree/nova/api/openstack/compute/rest_api_version_history.rst?h=stable/rocky#n177

But after we uses the cinder new attach workflow, this feature is broken, as when we delete the attachment
the volume status changed to "reserved" and we cannot detach the volume with this status.