Refactored Client to use Keystone Sessions

[OpenStack Infra]

https://review.openstack.org/127862

Dear documentation bug triager. This bug was created here because we did not know how to map the project name "openstack/python-barbicanclient" to a launchpad project name. This indicates that the notify_impact config needs tweaks. You can ask the OpenStack infra team (#openstack-infra on freenode) for help if you need to.

commit ddec180c419132589fac4d689ec1904b1b698f24
Author: Douglas Mendizabal <email address hidden>
Date: Sun Oct 12 20:25:07 2014 -0500

    Refactored Client to use Keystone Sessions

    This CR changes the Client to use Keystone Sessions exclusively. All
    authentication that was previously available in barbicanclient is
    removed so that we can defer all authentication to keystoneclient.

    Unit tests for the client module have been refactored to test the new
    functionality.

    The README file has been updated to give an example of how to
    authenticate with Identity v3 using Sessions.

    The Client will now give priority to an endpoint that is passed in over
    endpoints found in the service catalog, which closes bug #1276002. This
    is helpful for development, where you might be running an instance of
    Barbican locally that uses a Keystone instance for authentication that
    does not have the Barbican service in its catalog.

    The CLI uses Keystone API v3 as the default authentication method, but
    can also use v2.0.

    DocImpact
    Implements: blueprint use-keystone-sessions
    Closes-Bug: #1276002

    Change-Id: I9d07cb50143c1f5cafea48318018a205f745999f