Missing error handle for quota

[Alex Xu]

Quota should handle error by 'quantum.api.resource.Resource' same as core resource

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/21197

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/21197
Committed: http://github.com/openstack/quantum/commit/987b1a35cdb3631ab759b5ee6b63ad6ecb8e1753
Submitter: Jenkins
Branch: master

commit 987b1a35cdb3631ab759b5ee6b63ad6ecb8e1753
Author: He Jie Xu <email address hidden>
Date: Tue Feb 5 19:05:53 2013 +0800

    Wrap quota controller with resource.Resource

    Fixes bug 1116137

    Currently the format of error message returned by quota extension was
    different with quantum other resource. Other resource will return as
    json(eg, '{"QuantumError": "error message"}'). But quota extension only
    return messages without any format.
    'quantum.api.v2.resource.Resource' provider error messages processing.
    So wrap quota controller with it.

    By the way, fix some small stuff:
    * Use specific exception 'QuotaTenantNotFound' instead of generic exception.
    * Correct error message.
    * Use attribute mapping checking the request body.

    Change-Id: I71261198aa79e9ed8e0ae672de32552abdbf45c1