added tenantId/projectId to volume and snapshot

added tenant id to  volume and project id to snapshot
@demobox Hi! No, this is actually the OpenStack Cinder Extended Volume Attriibutes [extension](https://github.com/openstack/cinder/blob/master/cinder/api/contrib/extended_snapshot_attributes.py). I just noticed that this class is missing a field, so I plan to do full review of this PR when I get some time today.