return 500 if diskpool not exists when add disks to vm

[Huang Rui]

Request body:
'[{u'disk_pool': u'ECKD:notexist', u'size': u'1g'}]' for guest 'RST95754'.

Error msg:
{u'rs': 402, u'overallRC': 4, u'modID': 1, u'rc': 5, u'output': u'', u'errmsg': u"SMUT error: SMUT request failed. RequestData: 'getHost diskpoolspace noexist', Results: '{'rs': 402, 'errno': 0, 'strError': '', 'overallRC': 4, 'rc': 5, 'response': ['(Error) ULTGHO0402E No information was found for the specified pool(s): noexist']}'"}

Should return 404 if specified disk pool not exists.

[jichenjc (jichenjc)]

we need add a functional test for it if possible ...

[cao biao (flytiger)]

In wsgi code, we have handler about this:

req.response.status = util.get_http_code_from_sdk_return(info,
        additional_handler=util.handle_not_found)

if diskpool not found 'handle_not_found' will found it and change the status code to 404.
(Pdb) req
<Request at 0x3fff5b1c080 GET http://9.60.29.127:8888/host/diskpool?poolname=ECKD:dsaf>
(Pdb) req.response
<Response at 0x3fff5b1c048 404 Not Found>

as we can see, http code has been changed.

The problem is we didn't change the content of req.response.text.

In restclient, we just use response.text as the return results.

I will think about it and try to get a solution.