Change spec since v2 api is used as default

Since the cinder endpoint API version has been changed to v2 in
https://review.openstack.org/#/c/130738, the spec needs to be
adapted to this change accordingly.

This patch will break unit test unless the patch in
https://review.openstack.org/#/c/130738 is merged, because the API
version is changed in cookbook-openstack-common project.

I've run unit test in my local env successfully with these two
matched patches.

Change-Id: I28d182ff9e26fd31e5cd4f713dbffde3f04807dc
Closes-bug: #1385099
Merge "Change spec since v2 api is used as default"