zaqar raise 500 erro when create message with invalid body

[wangxiyuan]

reproduce:
123 is the queue name.
456 is the message body.

openstack message post 123 456 --client-id 86e0f939-6791-4e5e-b8a2-e11bfb827982

Then zaqar will raise 500 error

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/518682

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/518682
Committed: https://git.openstack.org/cgit/openstack/zaqar/commit/?id=bf6d42b2e9e98c69a7bff818b583045d12ce58e0
Submitter: Zuul
Branch: master

commit bf6d42b2e9e98c69a7bff818b583045d12ce58e0
Author: wangxiyuan <email address hidden>
Date: Thu Nov 9 16:03:03 2017 +0800

    Add input type check

    zaqar raises 500 erro when create message with integer format body.
    Because that json.loads() doesn't check the "integer like" string.

    Change-Id: Icafa829fa5f5ce3afcafc40f46c39ea8adcc836d
    Cloese-bug: 1731170