Fix barbicanclient deprecation

[Spyros Trigazis]

From the unit test output:
2017-12-05 10:17:53.436241 | ubuntu-xenial | /home/zuul/src/git.openstack.org/openstack/magnum/.tox/py27/local/lib/python2.7/site-packages/barbicanclient/__init__.py:61: UserWarning: The containers module is moved to barbicanclient/v1 directory, direct import of barbicanclient.containers will be deprecated. Please import barbicanclient.v1.containers instead.
2017-12-05 10:17:53.436444 | ubuntu-xenial | % (name, name, name))
2017-12-05 10:17:53.436664 | ubuntu-xenial | /home/zuul/src/git.openstack.org/openstack/magnum/.tox/py27/local/lib/python2.7/site-packages/barbicanclient/__init__.py:61: UserWarning: The secrets module is moved to barbicanclient/v1 directory, direct import of barbicanclient.secrets will be deprecated. Please import barbicanclient.v1.secrets instead.
2017-12-05 10:17:53.436714 | ubuntu-xenial | % (name, name, name))

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/526650

[OpenStack Infra (hudson-openstack)]

Change abandoned by Spyros Trigazis (strigazi) (<email address hidden>) on branch: master
Review: https://review.openstack.org/526650
Reason: in favor of https://review.openstack.org/#/c/532441

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/532441
Committed: https://git.openstack.org/cgit/openstack/magnum/commit/?id=54cd3caf1061fe1132e3b0dd0d885e76abc7f490
Submitter: Zuul
Branch: master

commit 54cd3caf1061fe1132e3b0dd0d885e76abc7f490
Author: Ricardo Rocha <email address hidden>
Date: Wed Jan 10 07:37:52 2018 +0000

    Use barbicanclient.v1 instead of barbicanclient

    Direct import of barbicanclient is being deprecated, we should use
    barbicanclient.v1 as per the warning message.

    Closes-Bug: #1737145

    Change-Id: I59d9ecfefd6a432cb8004da0d3676c576e53c5f0

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/magnum 6.0.0 release.