Previously, we hardcoded a v2.0 path to use when validating requests
against Keystone. Now, the version to use may be specified in a new
auth_version config option.
In the future, we may want to implement some form of version
discovery, but that will be complicated by:
* trying to determine whether the S3 extension is actually enabled for a
given version (particularly since the extensions endpoint [1] seems to
have gone away in v3), and
* needing to be able to perform this detection as part of the
client-request cycle, in case Keystone is down when the proxy is
coming up.
[1] http://developer.openstack.org/api-ref/identity/v2/index.html?expanded=list-extensions-detail
Change-Id: I3a9c702123fd1b76d45214a89ec0583caf3719f0
2a48861248