API Validation error could be more helpful if we provide the field name in the error message

[Saurabh Surana]

The error message that I received here, was clear about what the issue is, but it didn't tell me anything about where the validation has failed (for which field specifically). This will be helpful if we have multiple of these fields in the object which can go wrong

# trove-cli backup create --name Test --instance beb407e9-ae07-49ea-8cde-c1015ac5caee
REQUEST:
curl -i https://<API>/v1.0/<TenantID>/backups -X POST -H "X-Auth-Project-Id: <Tenant>" -H "User-Agent: python-troveclient" -H "Content-Type: application/json" -H "Accept: application/json" -H "X-Auth-Token:<Token>" -d '{"backup": {"instance": "beb407e9-ae07-49ea-8cde-c1015ac5caee", "name": "Test", "description": null}}'
BODY: {
    "backup": {
        "description": null,
        "instance": "beb407e9-ae07-49ea-8cde-c1015ac5caee",
        "name": "Test"
    }
}

RESPONSE HEADERS: {'date': 'Tue, 16 Jul 2013 22:18:15 GMT', 'status': '400', 'content-length': '90', 'content-type': 'application/json; charset=UTF-8'}
RESPONSE BODY : {
    "badRequest": {
        "code": 400,
        "message": "Validation error: None is not of type 'string'"
    }
}
Validation error: None is not of type 'string' (HTTP 400)

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/37706

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/37706
Committed: http://github.com/openstack/trove/commit/988d666af7e9d4f6c5bb036f99dc45e54fe5672a
Submitter: Jenkins
Branch: master

commit 988d666af7e9d4f6c5bb036f99dc45e54fe5672a
Author: justin-hopper <email address hidden>
Date: Thu Jul 18 08:45:36 2013 -0700

    Added param name to validation error messages

        Validation errors now pre-fixed with param name so that its
        easier to troubleshoot

    Fixes: bug 1201993

    Change-Id: Icff176de9f18fe08749473ee3d68c70c55be2c9c