Add test coverage for volume types

This PS adds coverage for volume types policies, specifically
those that test creating, updating and deleting a volume type
which enforces "volume_extension:types_manage" [0].

[0] https://github.com/openstack/cinder/blob/4ca4f644008f4c89edc472cacda19050367ba54a/cinder/policies/volume_type.py#L26

Change-Id: I38b88f7ab86635891141cda801b1ec9cf2758431
1 file changed