The context wrapper classes under castellan.common.credentials were
missing an auth_url property resulting in calls to get_endpoint()
failing with 'Could not determine a suitable URL for the plugin' unless
users set barbican/auth_endpoint.
Change-Id: I1be3a1e11e3f4c2170062927ad359bf679eb25d9
Closes-Bug: #1497993
It wasn't clear to me as a newcomer how to init a CONF object with my
own config file. Make the docs more clear around this. Also the
context=None arg to credential_factory is not needed.
Change-Id: Id633718fd19e0fe9b1627b64a2f50d751eeb93a2
