Changing gate on devstack identity v3 only voting
Changing gate on devstack identity v3 only voting

Keystone team decided to deprecate API v2.0 on Mitaka,
since the API v3 it's now the stable API version, this
patch change the devstack gate to be voting.

This patch is part of the plan on this etherpad:
https://etherpad.openstack.org/p/v3-only-devstack

Besided that, we investigate a couple of issues related to this point
and in a few points, we need to work on:

* Lack of "v3 only" jobs on gates (job on Tempest and Devstack be
  voting, create other service v3 only jobs)
* V3 only devstack fails in some projects like Ironic;
* Lack of keystoneauth session usage in some service clients;
* Delete the Hardcoded v2.0 usage like using v2 url, tenant variables;
* Remove the Keystone CLI usage, like in Nova gate;
* Change v2.0 service tokens to be v3: Hardwritten, automated tools
* OpenStack Client Config
* Add v3 operations tests in Tempest

Change-Id: I3fcc09475b8e76d2a7d95934ba45c6b3a6c4546e

dongwenjuan/project-config,Tesora/tesora-project-config,Tesora/tesora-project-config,openstack-infra/project-config,openstack-infra/project-config,dongwenjuan/project-config