Generate the user_agent from adapter and session

[Jamie Lennox]

We've had a way to provide a user_agent to requests however that requires the calling process to correctly specify something useful. We then added a way to determine the user agent, which provides some sort of guess at the main process but doesn't tell you all the pieces.

Instead we need a way to generate a user agent string from the pieces being used.

We need to be able to specify both the service that is making a request and the client that it is being made through. This can be seperated into information provided by the client (via the adapter) so that keystoneclient can always provide its own version. And then the code that constructs the session can provide the service information.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/357633

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/357633
Committed: https://git.openstack.org/cgit/openstack/keystoneauth/commit/?id=eb5571a6ca053ecde08234031debdc8923a5ce9a
Submitter: Jenkins
Branch: master

commit eb5571a6ca053ecde08234031debdc8923a5ce9a
Author: Jamie Lennox <email address hidden>
Date: Fri Aug 19 16:32:03 2016 +1000

    Allow specifying client and service info to user_agent

    Allow specifying a service name and version to the session and a client
    name and version to the adapter. The way this will work is that
    libraries such as keystoneclient will pass client_name and
    client_version when creating their adapter. Then when nova or another
    service creates a session it will provide the service name and version.
    The combination of these will be used to provide a meaningful user
    agent.

    Change-Id: Ibe516d9b248513579d5e8ca94015c4ae9c00f3f9
    Closes-Bug: #1614846

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/keystoneauth 2.14.0 release.