Sheepdog driver doesn't implement backup_volume and restore_backup

[YAMADA Hideki]

tempest api volume test fails.

ubuntu@ip-172-31-16-41:/opt/stack/tempest$ ./tools/pretty_tox.sh tempest.api.volume.admin.test_volumes_backup
running testr

(snip)

tempest.api.volume.admin.test_volumes_backup.VolumesBackupsV2Test.test_volume_backup_create_get_detailed_list_restore_delete [1.573678s] ... FAILED
{1} tempest.api.volume.admin.test_volumes_backup.VolumesBackupsV1Test.test_volume_backup_create_get_detailed_list_restore_delete [2.442452s] ... FAILED

(snip)

======
Totals
======
Ran: 2 tests in 10.0000 sec.
 - Passed: 0
 - Skipped: 0
 - Failed: 2
Sum of execute time for each test: 4.0161 sec.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/162927

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/162927
Committed: https://git.openstack.org/cgit/openstack/cinder/commit/?id=23e7943b1df4d5c567db69ee44e85242f8aff7a4
Submitter: Jenkins
Branch: master

commit 23e7943b1df4d5c567db69ee44e85242f8aff7a4
Author: YAMADA Hideki <email address hidden>
Date: Tue Mar 10 05:13:02 2015 +0000

    Add backup/restore methods to Sheepdog driver

    The backup tests fail when running tempest.
    The Sheepdog driver has not implemented backup/restore methods yet.

    Co-Authored-By: Teruaki Ishizaki <email address hidden>
    Change-Id: I8f6a82b046cfd1268092cc79111b9faedafe3c8b
    Closes-Bug: #1426440
    Related-Bug: #1444899