Create flavor accepts invalid href

POST /flavors accepts href values which are empty/ invalid (not in uri format) & returns success HTTP 204

Expected Result: HTTP 400 with appropriate error message.

See request/response details from the tests below.

root: INFO: ========================================================
root: INFO: Test Case....: test_create_flavor_negative_tests_1_empty_href
root: INFO: Created At...: 2014-10-14 10:23:37.110348
root: INFO: No Test description.
root: INFO: ========================================================
cafe.engine.http.client: DEBUG: (<tests.api.utils.client.PoppyClient object at 0x10689fbd0>, 'POST', 'http://0.0.0.0:8888/v1.0/flavors') {'headers': {'Content-Type': 'application/json', 'X-Project-Id': u'650278', 'X-Auth-Token': u'985a88c47abb4663981ca988eacbd1d1'}, 'params': {}, 'verify': False, 'data': '{"id": "b14a9e07-53ad-11e4-90bd-28cfe91478b9", "providers": [{"links": [{"href": "", "rel": "provider_url"}], "provider": "ChinaCache"}]}'}
requests.packages.urllib3.connectionpool: INFO: Starting new HTTP connection (1): 0.0.0.0
requests.packages.urllib3.connectionpool: DEBUG: "POST /v1.0/flavors HTTP/1.1" 204 0
cafe.engine.http.client: DEBUG:
------------
REQUEST SENT
------------
request method..: POST
request url.....: http://0.0.0.0:8888/v1.0/flavors
request params..:
request headers.: {'Content-Length': '137', 'Accept-Encoding': 'gzip, deflate', 'X-Project-Id': u'650278', 'Accept': '*/*', 'User-Agent': 'python-requests/2.4.1 CPython/2.7.1 Darwin/11.4.2', 'Connection': 'keep-alive', 'X-Auth-Token': u'985a88c47abb4663981ca988eacbd1d1', 'Content-Type': 'application/json'}
request body....: {"id": "b14a9e07-53ad-11e4-90bd-28cfe91478b9", "providers": [{"links": [{"href": "", "rel": "provider_url"}], "provider": "ChinaCache"}]}

cafe.engine.http.client: DEBUG:
-----------------
RESPONSE RECEIVED
-----------------
response status..: <Response [204]>
response time....: 0.348796844482
response headers.: {'date': 'Tue, 14 Oct 2014 14:23:40 GMT', 'content-length': '4', 'location': 'http://0.0.0.0:8888/v1.0/flavors/b14a9e07-53ad-11e4-90bd-28cfe91478b9', 'server': 'WSGIServer/0.1 Python/2.7.1'}
response body....:

======================================================================
FAIL: test_create_flavor_negative_tests_6_invalid_href (tests.api.flavors.test_flavors.TestCreateFlavors)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/Users/malini.kamalambal/github/poppyenv/lib/python2.7/site-packages/ddt.py", line 114, in wrapper
    return func(self, *args, **kwargs)
  File "/Users/malini.kamalambal/github/poppy/tests/api/flavors/test_flavors.py", line 69, in test_create_flavor_negative_tests
    self.assertEqual(resp.status_code, 400)
AssertionError: 204 != 400
-------------------- >> begin captured logging << --------------------
root: INFO: ========================================================
root: INFO: Test Case....: test_create_flavor_negative_tests_6_invalid_href
root: INFO: Created At...: 2014-10-14 12:54:48.540013
root: INFO: No Test description.
root: INFO: ========================================================
cafe.engine.http.client: DEBUG: (<tests.api.utils.client.PoppyClient object at 0x10a15fbd0>, 'POST', 'http://0.0.0.0:8888/v1.0/flavors') {'headers': {'Content-Type': 'application/json', 'X-Project-Id': u'650278', 'X-Auth-Token': u'985a88c47abb4663981ca988eacbd1d1'}, 'params': {}, 'verify': False, 'data': '{"id": "cf5af3f3-53c2-11e4-8fbf-28cfe91478b9", "limits": null, "providers": [{"links": [{"href": "watermelon", "rel": "provider_url"}], "provider": "ChinaCache"}]}'}
requests.packages.urllib3.connectionpool: INFO: Starting new HTTP connection (1): 0.0.0.0
requests.packages.urllib3.connectionpool: DEBUG: "POST /v1.0/flavors HTTP/1.1" 204 0
cafe.engine.http.client: DEBUG:
------------
REQUEST SENT
------------
request method..: POST
request url.....: http://0.0.0.0:8888/v1.0/flavors
request params..:
request headers.: {'Content-Length': '163', 'Accept-Encoding': 'gzip, deflate', 'X-Project-Id': u'650278', 'Accept': '*/*', 'User-Agent': 'python-requests/2.4.1 CPython/2.7.1 Darwin/11.4.2', 'Connection': 'keep-alive', 'X-Auth-Token': u'985a88c47abb4663981ca988eacbd1d1', 'Content-Type': 'application/json'}
request body....: {"id": "cf5af3f3-53c2-11e4-8fbf-28cfe91478b9", "limits": null, "providers": [{"links": [{"href": "watermelon", "rel": "provider_url"}], "provider": "ChinaCache"}]}

cafe.engine.http.client: DEBUG:
-----------------
RESPONSE RECEIVED
-----------------
response status..: <Response [204]>
response time....: 0.0130360126495
response headers.: {'date': 'Tue, 14 Oct 2014 16:54:49 GMT', 'content-length': '4', 'location': 'http://0.0.0.0:8888/v1.0/flavors/cf5af3f3-53c2-11e4-8fbf-28cfe91478b9', 'server': 'WSGIServer/0.1 Python/2.7.1'}
response body....: