Show default attributes for queue

[OpenStack Infra]

https://review.openstack.org/286433
Dear bug triager. This bug was created since a commit was marked with DOCIMPACT.
Your project "openstack/zaqar" is set up so that we directly report the documentation bugs against it. If this needs changing, the docimpact-group option needs to be added for the project. You can ask the OpenStack infra team (#openstack-infra on freenode) for help if you need to.

commit e4a5fd488651f47489ecdf66c49b8e8ddb09127d
Author: wanghao <email address hidden>
Date: Tue Mar 1 15:58:33 2016 +0800

    Show default attributes for queue

    Currently Zaqar will support more built-in/reserved
    attributes in queue.
    We add two important attributes max_messages_post_size
    and max_message_ttl.

    So it's very useful for users that if they create a queue without
    metadata, when they query queue, Zaqar add those two attributes from
    config to queue metadata and then return.
    That will not be stuck if config is changed and user also can
    know what value it is.

    APIImpact
    DocImpact

    Change-Id: Icf9af8e357b2e2df363cd28ef3ca7f7f97a77744
    Implements: blueprint show-default-attributes-for-queue