This lets us use Keystone sessions against endpoints like swauth and
tempauth with code like:

    import keystoneauth1.loading
    import keystoneauth1.session
    import swiftclient

    loader = keystoneauth1.loading.get_plugin_loader('v1password')
    auth_plugin = loader.load_from_options(
        auth_url='http://saio:8080/auth/v1.0',
        username='test:tester',
        password='testing')
    keystone_session = keystoneauth1.session.Session(auth_plugin)

    conn = swiftclient.Connection(session=keystone_session)

The plugin includes an optional project_name option, which may be used
to override the swift account from the storage url that was returned.
Additionally, it includes enough infrastructure to support some commands
in python-openstackclient>=3.0:

    export OS_AUTH_TYPE=v1password
    export OS_AUTH_URL=http://saio:8080/auth/v1.0
    export OS_PROJECT_NAME=AUTH_test2
    export OS_USERNAME=test:tester
    export OS_PASSWORD=testing

    openstack token issue
    openstack catalog list
    openstack catalog show object-store
    openstack object store account show
    openstack container list
    openstack container create <container>
    openstack container save <container>
    openstack container show <container>
    openstack container delete <container>
    openstack object list <container>
    openstack object create <container> <file>
    openstack object save <container> <object>
    opsentack object show <container> <object>
    openstack object delete <container> <object>

Change-Id: Ia963dc44415f72a6518227e86d9528a987e07491