The os-volume_attachments APIs have their own policy settings defined,
yet were also checking the policy settings defined for the os-volumes
APIs. This should never have been the case, but especially not now
that the os-volumes APIs are deprecated and don't even work anymore
with newer microversions. This change removes the os-volumes policy
checks for os-volume_attachment API requests. The code will continue
to make os-volumes policy checks for os-volumes APIs, and
os-volume_attachment policy checks for os-volume_attachment APIs.
Removed the _items method, which was only being called from one place,
to resolve comments that policy checks should always happen immediately
upon entering the API methods.
Change-Id: I35aaedf5c4c49cb568fa06c2974f9a35aa2ffcc5
Closes-Bug: #1635358
UpgradeImpact