Attach and Detach actions are done in the novaclient, however
during the creation of Cinder a number of these methods were copied into
the Cinder client. This is dead code and just adds confusion, so let's
rip it out.
Change-Id: Ib96fe0cac26f19e7d9f2aa01c71ba9762e4f8b8e
Fixes: bug #1071003