Kombu RPC connector does not allow for different login methods

[Joe Harrison]

The kombu library allows connections such as:
Connection('amqp://', login_method='EXTERNAL', ssl={
    'ca_certs': '/etc/pki/tls/certs/something.crt',
    'keyfile': '/etc/something/system.key',
    'certfile': '/etc/something/system.cert',
    'cert_reqs': ssl.CERT_REQUIRED,
})

As you can see, a login method can be specified.
Being able to change this allows me to utilize the rabbitmq rabbitmq_auth_mechanism_ssl plugin (as I need to specify the EXTERNAL login_method)

However, it would be much easier if this could be configured with an option instead of mutilating source code when a change is required.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/67254

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/67254
Committed: https://git.openstack.org/cgit/openstack/oslo.messaging/commit/?id=98454aaf86b7da4d4ddd97b64c222c5da8c2c210
Submitter: Jenkins
Branch: master

commit 98454aaf86b7da4d4ddd97b64c222c5da8c2c210
Author: Joe Harrison <email address hidden>
Date: Thu Jan 16 19:06:31 2014 +0100

    Allow different login methods to be used with kombu connections

    Currently it is not possible to modify the login method used with
    kombu connections via configuration files, and requires modifying
    the source code to actually add a login method in the first place.
    This adds a configuration option (and default) which are passed
    along to the kombu connection.

    RabbitMQ allows three login method strings by default, but server
    side plugins allow arbitrarily named strings to be used as login
    methods and as such it is not possible to provide a fixed list of
    options to the user.

    DocImpact

    Change-Id: I5c62a8dd4125d42bb429d3985061e37a9d519fff
    Closes-Bug: #1269890