Username bug when calling predict

[dmitrypolo]

Currently in the predict method the logic is as follows:

prediction_url = urllib.parse.urljoin(self.url, os.path.join(
    self.username, 'models', modelName, 'predict'))
username = username if username else self.username
response = requests.post(
            url=prediction_url, 
            ...

The way this logic works is that it builds the prediction url with self.username always and never considers if you give the predict method a username along with the model and data. It should be switched to look like this:

username = username if username else self.username
prediction_url = urllib.parse.urljoin(self.url, os.path.join(
    username, 'models', modelName, 'predict'))

Unfortunately the repo is read-only so I can not push the change to a remote branch and open a PR. In the short-term I have modified my source code to work as intended.