update to version 1.9.0
* Fix Unicode error printing extra-specs
* Fix batch deleting issue in volume_type.unset_keys()
* List manageable volumes and snapshots
* base.Resource not define __ne__() built-in function
* Make Resource class's function can be wraped by api_version
* Add group types and group specs
* Fix Service.__repr__ to remove the undefined attribute
* Wrap group type and group spec with api_version
* Wrap volume_backup's update function with api_version
* Fix _get_rate_limit when resp is None
* Make __repr__ print encryption_id for VolumeEncryptionType class
* Fixing parsing problem of cascade in client
* Fix useless api_version of Manager class
* Add cluster related commands
* Add Negative tests for cinder volume extend command
* Fix python 2,3 compatibility issue with six
* Use 'six' instead of oslo_utils.strutils.six
* Add generic volume groups
* Support for snapshot force delete
* Add backup-update
* Add Python3.5 classifier and venv
* OS_TENANT_NAME is not required when we have OS_PROJECT_NAME
* Wrap cluster related function with api_version
* Fix argument order for assertEqual to (expected, observed)
* Make APIVersion's null check more pythonic
* Switch to keystoneauth
* Fix output error for type-show command
* Support name option for volume restore
* Replace OpenStack LLC with OpenStack Foundation