Update the 'list' method of volumeprovider about Cinder

[dengshaolin]

Source Code:

    def list(self):
        LOG.info(_LI("Start to retrieve all docker volumes from Cinder"))

        docker_volumes = []
        try:
            search_opts = {'metadata': {consts.VOLUME_FROM: 'fuxi'}}

'fuxi' in search_opts should be extracted from CONF:
search_opts = {'metadata': {consts.VOLUME_FROM: CONF.volume_from}}

Otherwise, CONF.volume_from changed, cmd docker volume ls could not obtain the expected result.

[OpenStack Infra (hudson-openstack)]

Change abandoned by Zhang Ni (<email address hidden>) on branch: master
Review: https://review.openstack.org/351143
Reason: resubmit

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/351501
Committed: https://git.openstack.org/cgit/openstack/fuxi/commit/?id=794f9329f5ed78789ee324c754d81873e27ce27d
Submitter: Jenkins
Branch: master

commit 794f9329f5ed78789ee324c754d81873e27ce27d
Author: zhangni <email address hidden>
Date: Fri Aug 5 14:15:37 2016 +0800

    Update the 'list' method of volumeprovider about Cinder

    'fuxi' in search_opts should be extracted from CONF:
    Otherwise, CONF.volume_from changed, cmd docker volume ls could not obtain the
    expected result

    Change-Id: I2d021d26a5c73f4d231ddc638dc204041ddce29b
    Closes-Bug: #1609763