This continues to update the name for volume type:
* Update a client method for volume type.
update: to update an existing volume type's name
* Update a command-line operations.
type-update: (adminitrator only) to update a volume type name
The corresponding cinder APIs change to update volume type name:
https://review.openstack.org/#/c/140906/
Implements: blueprint volume-type-description
Change-Id: I66adb7fd2a433e7443cb609046f64dbab3d9d4c7