204 response is not handled

[djangoliv]

The requests:

result = client.put(
'/cloud/project//kube//nodepool/',
desiredNodes=2,
maxNodes=4,
minNodes=1,
nodesToRemove=[],
)

return 204 but the the parse of the result faied.

In client.py

       try:
           json_result = result.json()
       except ValueError as error:
           raise InvalidResponse("Failed to decode API response", error)

=> simplejson.errors.JSONDecodeError: Expecting value: line 1 column 1 (char 0)

which is normal since 204 is a No Content response .

Regards

[djangoliv]

This is a PR for fixing this bug: #92

Regards