Test Volumes with glance should be skip when Glance is not avaialable

[Jaesang Lee]

Issue:

In some tests, it try to create volume with image
 "VolumesV2ImageMetadata",
 "test_create_from_bootable_volume",
 "test_bootable_volume_backup_and_restore",
so if glance isn't available, it cannot pass that test, fail always.

Fix:
Add skip method for check glance service.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/449524

[OpenStack Infra (hudson-openstack)]

Change abandoned by Jaesang Lee (<email address hidden>) on branch: master
Review: https://review.openstack.org/449524
Reason: This patch has errors when merged, I'll re-create new review.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/450157

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/450157
Committed: https://git.openstack.org/cgit/openstack/tempest/commit/?id=e4dc8fb3ab1fcb0ae0e83722c7c1e7abde0c7b94
Submitter: Jenkins
Branch: master

commit e4dc8fb3ab1fcb0ae0e83722c7c1e7abde0c7b94
Author: Jaesang Lee <email address hidden>
Date: Sat Mar 25 01:19:58 2017 +0000

    Add skip method for volume test with the glance service

    In some tests, it try to create volume with image
     "VolumesV2ImageMetadata",
     "test_create_from_bootable_volume",
     "test_bootable_volume_backup_and_restore",
    so it should be check Glance is available before test.
    If all tests in class is associate with glance, I used skip_checks,
    and otherwise, I used testtools.SkipIf

    Change-Id: I2302699f98b77b0ccad551ef11c4655544b3f827
    Closes-Bug: 1675700

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/tempest 16.0.0 release.