Add tests to check attachments are secure

A vulnerability was detected in Cinder that could allow users to access
other people's volumes.

The solution was to limit some of the operations on attached volumes to
only OpenStack services.

This patch adds some negative tests to check that a user cannot directly
call Cinder to detach a volume, force detach it, terminate its
connection, or delete its attachment.

Depends-On: I612905a1bf4a1706cce913c0d8a6df7a240d599a
Related-Bug: #2004555
Change-Id: Ice6532ce7943e9a9363e443515946865541d09c2
6 files changed