Volumes APIs returns a 500 error for an invalid entity body rather than 422

Description:
------------------

When Request body is sent as "Invalid JSON" request, HTTP 500 ERROR is returned instead of Bad Request exception(code :400).

Environment:
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Single node Folsom

Consider the following examples
LOG:
----------

1. Server Creation with invalid JSON

rajalakshmi_ganesan@ubuntu:~/latest_source/csbu-qa/AutomatedTests/python_tests/hp_regression/nova/nova_api_tests/volumes$ curl -i http://10.233.52.237:8774/v2/0deffdb2275c478f8689d9f430eca9f4/servers -X POST -H "X-Auth-Project-Id: admin" -H "User-Agent: python-novaclient" -H "Content-Type: application/json" -H "Accept: application/json" -H "X-Auth-Token: ebcf44ed8bcb4a5f90c9af83f6df6fad" -d '{"erver": {"min_count": 1, "flavorRef": "1", "name": "test-3", "imageRef": "bc81d48e-656f-4501-8909-3401121cdf5b", "max_count": 1}}'
HTTP/1.1 500 Internal Server Error
Content-Length: 128
Content-Type: application/json; charset=UTF-8
X-Compute-Request-Id: req-fdde490a-d3d9-4a19-9e48-12d105f996c4
Date: Mon, 10 Sep 2012 15:03:28 GMT

{"computeFault": {"message": "The server has either erred or is incapable of performing the requested operation.", "code": 500}}rajalakshmi_ganesan@ubuntu:~/latest_source/csbu-qa/AutomatedTests/python_tests/hp_regression/nova/nova_api_tests/volumes$

2. Volume Creation with invalid JSON

rajalakshmi_ganesan@ubuntu:~/latest_source/csbu-qa/AutomatedTests/python_tests/hp_regression/nova/nova_api_tests/volumes$ curl -i http://10.233.52.237:8776/v1/0deffdb2275c478f8689d9f430eca9f4/volumes -X POST -H "X-Auth-Project-Id: admin" -H "User-Agent: python-novaclient" -H "Content-Type: application/json" -H "Accept: application/json" -H "X-Auth-Token: 18561d9bc2cf4bd08d4747f3ef0d547c" -d '{"volumeeeeeee": {"display_name": null, "availability_zone": null, "volume_type": null, "display_description": null, "snapshot_id": null, "size": 1}}'
HTTP/1.1 500 Internal Server Error
Content-Length: 128
Content-Type: application/json; charset=UTF-8
X-Compute-Request-Id: req-0f381070-4370-4acf-a49d-ae35737b2e7c
Date: Mon, 10 Sep 2012 15:09:37 GMT

{"computeFault": {"message": "The server has either erred or is incapable of performing the requested operation.", "code": 500}}rajalakshmi_ganesan@ubuntu:~/latest_source/csbu-qa/AutomatedTests/python_tests/hp_regression/nova/nova_api_tests/volumes$

3. Attaching VOLUME to SERVER with invalid JSON

rajalakshmi_ganesan@ubuntu:~/latest_source/csbu-qa/AutomatedTests/python_tests/hp_regression/nova/nova_api_tests/volumes$ curl -i http://10.233.52.237:8774/v2/0deffdb2275c478f8689d9f430eca9f4/servers/fc36fc50-4318-43f2-ac40-c74ee08590f7/os-volume_attachments -X POST -H "X-Auth-Project-Id: admin" -H "User-Agent: python-novaclient" -H "Content-Type: application/json" -H "Accept: application/json" -H "X-Auth-Token: ebcf44ed8bcb4a5f90c9af83f6df6fad" -d '{"volumeattachment": {"device": "/dev/vdz", "volumeId": "6cc71651-d3df-43e0-8d6f-876e7f3cefe2"}}'
HTTP/1.1 500 Internal Server Error
Content-Length: 128
Content-Type: application/json; charset=UTF-8
X-Compute-Request-Id: req-4a5cca99-8e33-49e5-971d-f95f5b65d5c3
Date: Mon, 10 Sep 2012 15:08:35 GMT

{"computeFault": {"message": "The server has either erred or is incapable of performing the requested operation.", "code": 500}}rajalakshmi_ganesan@ubuntu:~/latest_source/csbu-qa/AutomatedTests/python_tests/hp_regression/nova/nova_api_tests/volumes$