RBD helper utils in libvirt driver code need to be moved to separate module

[Daniel Berrange]

The libvirt imagebackend.py file has alot of helper APIs for dealing with the RBD utilities. It is desirable that these all be isolated in a standalone rbd.py file, to be called by the imagebackend.py This will make the core logic in imagebackend.py easier to follow and make the rbd helpers easier to test.

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/94293
Committed: https://git.openstack.org/cgit/openstack/nova/commit/?id=8230b751fbb4c41a3da987fea335d06f05e07272
Submitter: Jenkins
Branch: master

commit 8230b751fbb4c41a3da987fea335d06f05e07272
Author: Josh Durgin <email address hidden>
Date: Wed Jan 22 14:44:11 2014 -0800

    Move libvirt RBD utilities to a new file

    This will make it easier to share rbd-related code with cinder and glance.
    Port the applicable unit tests over from cinder.

    Closes-Bug: #1346092
    Co-Authored-By: Dmitry Borodaenko <email address hidden>
    Signed-off-by: Josh Durgin <email address hidden>
    Signed-off-by: Dmitry Borodaenko <email address hidden>
    Change-Id: I614b8e2bf0ea9e71a73772cbabcf812b39fa8a34

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/94294
Committed: https://git.openstack.org/cgit/openstack/nova/commit/?id=13e2bd02a5b50973f95eb3d8fc0af4e0702e3381
Submitter: Jenkins
Branch: master

commit 13e2bd02a5b50973f95eb3d8fc0af4e0702e3381
Author: Dmitry Borodaenko <email address hidden>
Date: Thu Mar 13 14:33:11 2014 -0700

    Use library instead of CLI to cleanup RBD volumes

    'rbd list' CLI returns error code when there are no rbd volumes, which
    causes problems during live migration of VMs with RBD backed ephemeral
    volumes. It's safer to use the library that only raises an exception in
    case of a real problem.

    The only case where rbd CLI is still justified is import, which is
    needed to correctly import sparse image files.

    All code related to cleanup of RBD volumes is moved to rbd.py, this
    fixes a yo-yo problem with single-use methods scattered across 3
    different files, and minimizes impact of this fix on imports in
    imagebackend and utils.

    Closes-Bug: #1346092
    Change-Id: I92cd6b16fbd93b377fe47b15d22efbbf68d02513
    Signed-off-by: Dmitry Borodaenko <email address hidden>

[Jens Rosenboom (frickler)]

This seems to cause a bug at least when using devstack, please check https://bugs.launchpad.net/nova/+bug/1352595