Cinder REST API allows one to use a special query parameter
named "all_tenants" to list resources from all projects (tenants)
through the REST API:
`/v3/{project_id}/volumes/detail?all_tenants=1`
However, this option is hardly documented anywhere besides
`/v3/{project_id}/volumes/summary`. So add them.
Change-Id: Ia9cc9e20c3b333a054c90f07e952b61dfad8529e
Closes-Bug: #1743800
ba9eaf27af