The nova client (used by the InstanceLocalityFilter for example)
seems to have obscure config options (compared to other projects),
and seems it is buggy too. Fix this by introducing a [nova] section,
where the usual auth parameters can be put (auth_type, auth_url,
username, password, etc...), and deprecate the old options.
Also doesn't play with the Service Catalog, the authentication plugins
can handle it, use a Token authentication plugin when using
the user context, and removed the separate usage of the admin endpoint.
Change-Id: I55613793c8f525a36ac74636f47d7ab76f5c7e39
Closes-bug: #1686616
DocImpact: to use a Nova connection (e.g. for InstanceLocalityFilter),
one has to configure the [nova] section.
da93e11794