setting keystone preferred-api-version 3 dashboard authentication not working

[Lirim]

When enabling preferred-api-version: 3 on keystone can not authenticate through dashboard. My env settings:

root@juju-machine-1-lxc-7:/home/ubuntu# env | grep OS
OS_REGION_NAME=RegionOne
OS_USER_DOMAIN_NAME=admin_domain
OS_PROJECT_NAME=admin
OS_IDENTITY_API_VERSION=3
OS_PASSWORD=0p3nstack
OS_AUTH_URL=http://10.48.4.76:5000/v3
OS_USERNAME=admin
OS_TENANT_NAME=admin
LESSCLOSE=/usr/bin/lesspipe %s %s
OS_PROJECT_DOMAIN_NAME=Default

running openstack --debug server list responds successfully to keystone endpoints with v3 enabled. However looking into /etc/openstack-dashboard/local_settings.py I see the settings are still with v2.0

OPENSTACK_HOST = "10.48.4.76"
OPENSTACK_KEYSTONE_URL = "http://%s:5000/v2.0" % OPENSTACK_HOST
OPENSTACK_KEYSTONE_DEFAULT_ROLE = "Member"

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/335056

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/335056
Committed: https://git.openstack.org/cgit/openstack/charm-keystone/commit/?id=3c1bcdcef3ed0fcf165b0b2c9517a8a4aff8b8c2
Submitter: Jenkins
Branch: master

commit 3c1bcdcef3ed0fcf165b0b2c9517a8a4aff8b8c2
Author: Liam Young <email address hidden>
Date: Tue Jun 28 08:20:27 2016 +0000

    Add admin domain id to identity relation

    Add the admin domain id (not name) to the data passed to clients
    down the identity-service relation. Some clients (eg Horizon) require
    the admin domain id for local configuration.

    Change-Id: Idfbd09fa62e628958139f77b9d06f602783e3619
    Partial-Bug: 1595685