Comment 2 for bug 1712999

Reviewed: https://review.openstack.org/506259
Committed: https://git.openstack.org/cgit/openstack/charm-openstack-dashboard/commit/?id=780381e6c4fffddbe5c7e4a43d213c63f687de82
Submitter: Zuul
Branch: master

commit 780381e6c4fffddbe5c7e4a43d213c63f687de82
Author: Michael Skalka <email address hidden>
Date: Thu Sep 21 11:19:18 2017 -0400

    Add default_domain config option.

    This commit adds the default-domain config option to limit
    the login page to only the specifed domain. For use with a single
    domain environment where users are only given a login.

    When considering a single domain usecase for users (admin_domain for
    administration, then example_domain for all other users), it would
    be handy for users not to input their domain name, but only username
    and password to login.

    By setting two lines below, we can create a separate dashboard instance
    for non-admin users only.

    OPENSTACK_KEYSTONE_MULTIDOMAIN_SUPPORT=False
    OPENSTACK_KEYSTONE_DEFAULT_DOMAIN=example_domain

    However, the current local_settings.py template does not allow that.

    This change adds the 'default-domain' configuration option which modifies
    local_policy.py to set the two configuration flags outlined in the bug.
    If the config option is not set the charm will behave as before, enabling
    the user to specify the domain at login.

    This does no validation to ensure the domain exists, so it is up to the user
    to supply a valid domain name.

    Closes-Bug: 1712999
    Change-Id: I316372ae305a4ba10e4d8ba047f23a317836b960