Replaces the original patch:
https://review.openstack.org/#/c/387712/
Use the python-cinderclient WIP:
https://review.openstack.org/#/c/387716/
Here's what you can do currently:
`cinder attachment-create <volume-uuid>`
Currently only tested/implemented the reserve piece
Will create an attachment object, set volume to a
status of 'reserved'
`cinder attachment-list`
Simple list output of attachments
`cinder attachment-show <attachment-uuid>`
Detailed list of specified attachment
`cinder attachment-delete <attachment-uuid>`
Removes an attachment
Change-Id: Ie15233c99d91de67279b56d27a5508c5ea98d769