copy volume to image/image to volume doesn't detach volume.

[Walt Boring]

The iSCSI base driver's copy volume to image and copy image to volume code doesn't include a call
to detach a volume once the copying is done.

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/32650
Committed: http://github.com/openstack/cinder/commit/0a155bea36aee44c5e7ecd026efe9537eee25eda
Submitter: Jenkins
Branch: master

commit 0a155bea36aee44c5e7ecd026efe9537eee25eda
Author: Walter A. Boring IV <email address hidden>
Date: Tue Jun 11 15:27:56 2013 -0700

    Add Brick iSCSI attach/detach.

    This patch adds the new brick initiator connector object
    which contains the code to do volume attach and detach to a host
    machine. It includes hooks to work in both cinder and nova.
    Nova has different exec wrapper and it also needs to talk to a
    hypervisor at certain points during detach.

    This patch also pulls the copy/pasted code from nova in the base
    ISCSIDriver's _attach_volume method to use this new brick library.

    This patch also includes a fix in the ISCSIDriver's
    copy_volume_to_image code that didn't actually detach a volume
    when it was done with the operation.
    Bug 1194962

    This patch also includes a fix for iSCSI detaches where the
    iSCSI LUN wasn't being removed from the system until the very
    last detach issues an iscsiadm logout.
    Bug 1112483

    This patch includes a fix for iSCSI multipath detaches where
    the multipath device and the iSCSI LUNs for the multipath device
    were never removed from the kernel.
    Bug 1112483

    Blueprint cinder-refactor-attach

    Change-Id: Ieb181f896adb9230bbb6a2e5c42f261d61a0f140