Create server(POST) using invalid personality contents is not raising BadRequest

Description:
 ----------------
 On creating a server with invalid personality contents we are getting a server error (HTTP 500) instead of raising the expected BadRequest Exception.

Environment:
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Single node Folsom

CURL Command:
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root@ubuntu28folsom:~/launchpad_nova/nova# curl -i http://127.0.0.1:8774/v2/c77eea6f6a7a4ded95b3235794792823/servers -X POST -H "X-Auth-Project-Id: demo" -H "User-Agent: python-novaclient" -H "Content-Type: application/json" -H "Accept: application/json" -H "X-Auth-Token: fef1136d5d194609ab22f039f10b5c57" -d '{"server": {"min_count": 1, "flavorRef": "1", "personality": [{"path": "/etc/banner.txt", "contents": "b25zLiINCg0KLVJpY2hhcmQgQ$$%QQmFjaA=="}], "name": "tsttemp2", "imageRef": "b8ca6857-5286-424c-8462-5dd0528edb63", "max_count": 1}}'
HTTP/1.1 500 Internal Server Error
Via: 1.1 HYSPROXY2
Connection: Keep-Alive
Proxy-Connection: Keep-Alive
Content-Length: 128
Date: Thu, 13 Sep 2012 16:39:15 GMT
Content-Type: application/json; charset=UTF-8
X-Compute-Request-Id: req-ca58aa01-18fe-480a-b693-3d797e654507

{"computeFault": {"message": "The server has either erred or is incapable of performing the requested operation.", "code": 500}}root@ubuntu28folsom:~/launchpad_nova/nova#
root@ubuntu28folsom:~/launchpad_nova/nova#

Expected result:
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 Should raise BadRequest