Alternative queuing policies for swift middleware

[OpenStack Infra]

https://review.openstack.org/#/c/33800/
commit 7e6efd504273aa58286b8014381bc7946cfd82fb
Author: Mehdi Abaakouk <email address hidden>
Date: Thu Jun 20 13:10:35 2013 +0200

    Alternative queuing policies for swift middleware

    This change allow to configure the behavior of swift middleware
    when rabbitmq is down.

    3 policies are available:
    - default: wait until it comes back, all swift requests are stalled
      if rabbit_max_retries <= 0, or return 50X if rabbit_max_retries > 0
    - drop: don't publish the sample
    - queue: create a local queue of publisher_queue_length sample

    default is the actual behavior before this change.

    Fixes: bug #1192918
    DocImpact

    Change-Id: Ib0dae8f0ab787cfc2a1ac59517f928fe02bb9eee