Add config option for Barbican endpoint interface

[Ellen Batbouta]

Today the Barbican key manager endpoint is created using the public interface as shown here:

      def _get_barbican_endpoint(self, auth, sess):
      if self.conf.barbican.barbican_endpoint:
             return self.conf.barbican.barbican_endpoint
      else:
            service_parameters = {'service_type': 'key-manager',
                                  'service_name': 'barbican',
                                  'interface': 'public'}

The public interface is not always desirable and a user should be able to configure this parameter to be any of the following values; public, internal or admin. The default value will be public.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/565529

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/565529
Committed: https://git.openstack.org/cgit/openstack/castellan/commit/?id=777b1cce100f0d523a135a7830c6679ad7c9ab41
Submitter: Zuul
Branch: master

commit 777b1cce100f0d523a135a7830c6679ad7c9ab41
Author: Ellen Batbouta <email address hidden>
Date: Tue May 1 12:22:20 2018 -0400

    Add config option for Barbican endpoint type

    This change willl allow the user to specify the endpoint
    type for Barbican. The allowed values are: public, internal,
    and admin. The default value will be 'public' since this is
    the current value.

    Change-Id: Ic89519ed3a9c347a9fff245ec231aa575b42f1ac
    Closes-bug: 1767473

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/castellan 0.18.0 release.