separate create and update rules for volume metadata

[Anna Sortland]

Both create() and update() in cinder/api/v2/volume_metadata.py call cinder/volume/api.py's update_volume_metadata.
However, these are 2 different operations and might require different policy rules. For example, an operator might want a policy where anybody can create volume metadata but only owner can update it. So it would be better to have a separate create_volume_metadata() function in api.py that create() would call.
We will also need a new rule for create. Looks like the rule for update is missing in default policy.json so should be added as well.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/356624

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/356624
Committed: https://git.openstack.org/cgit/openstack/cinder/commit/?id=9771c2cd4e32979358f8647e57b4bab355221c0d
Submitter: Jenkins
Branch: master

commit 9771c2cd4e32979358f8647e57b4bab355221c0d
Author: Yuriy Nesenenko <email address hidden>
Date: Wed Aug 17 20:15:03 2016 +0300

    Separate create and update rules for volume metadata

    This patch allows different policy rules for create and
    update volume metadata.

    Change-Id: I23dabd8866a9358c41eb3e048d91011a53c41cc3
    Closes-Bug: #1472042

[Thierry Carrez (ttx)]

This issue was fixed in the openstack/cinder 9.0.0.0b3 development milestone.