Fix fitbit error when trying to access token after upgrade.

[tchellomello]

Description:

Fix fibit sensor to correctly access oauth token after upgrade on 0.52

Related issue (if applicable): fixes #9152

Traceback:

"File "/srv/homeassistant/lib/python3.4/site-packages/homeassistant/components/sensor/fitbit.py", line 494, in update
ATTR_ACCESS_TOKEN: self.client.client.token['access_token'],
AttributeError: 'FitbitOauth2Client' object has no attribute 'token'"

Example entry for configuration.yaml (if applicable):

# sensors.yaml
- platform: fitbit
  monitored_resources:
    - "activities/distance"
    - "activities/minutesFairlyActive"
    - "activities/minutesLightlyActive"
    - "activities/minutesSedentary"
    - "activities/minutesVeryActive"
    - "activities/steps"
    - "devices/battery"
    - "sleep/efficiency"

Checklist:

If the code does not interact with devices:

• Local tests with tox run successfully. Your PR cannot be merged unless tests pass
• Tests have been added to verify that the new code works.

[tchellomello]

This PR still needs some work since once the token is expired, on a HASS restart it will throw the error below:

Aug 29 03:44:33 hass hass[3535]:   File "/opt/srv/homeassistant/.virtualenvs/hass-py36/lib/python3.6/site-packages/homeassistant/helpers/entity_component.py", line 164, in _async_setup_platform
Aug 29 03:44:33 hass hass[3535]:     SLOW_SETUP_MAX_WAIT, loop=self.hass.loop)
Aug 29 03:44:33 hass hass[3535]:   File "/usr/lib64/python3.6/asyncio/tasks.py", line 358, in wait_for
Aug 29 03:44:33 hass hass[3535]:     return fut.result()
Aug 29 03:44:33 hass hass[3535]:   File "/usr/lib64/python3.6/asyncio/futures.py", line 245, in result
Aug 29 03:44:33 hass hass[3535]:     raise self._exception
Aug 29 03:44:33 hass hass[3535]:   File "/usr/lib64/python3.6/concurrent/futures/thread.py", line 55, in run
Aug 29 03:44:33 hass hass[3535]:     result = self.fn(*self.args, **self.kwargs)
Aug 29 03:44:33 hass hass[3535]:   File "/opt/srv/homeassistant/.homeassistant/custom_components/sensor/fitbit.py", line 272, in setup_platform
Aug 29 03:44:33 hass hass[3535]:     authd_client.system = authd_client.user_profile_get()["user"]["locale"]
Aug 29 03:44:33 hass hass[3535]:   File "/opt/srv/homeassistant/.virtualenvs/hass-py36/lib/python3.6/site-packages/fitbit/api.py", line 252, in user_profile_get
Aug 29 03:44:33 hass hass[3535]:     return self.make_request(url)
Aug 29 03:44:33 hass hass[3535]:   File "/opt/srv/homeassistant/.virtualenvs/hass-py36/lib/python3.6/site-packages/fitbit/api.py", line 223, in make_request
Aug 29 03:44:33 hass hass[3535]:     response = self.client.make_request(*args, **kwargs)
Aug 29 03:44:33 hass hass[3535]:   File "/opt/srv/homeassistant/.virtualenvs/hass-py36/lib/python3.6/site-packages/fitbit/api.py", line 99, in make_request
Aug 29 03:44:33 hass hass[3535]:     exceptions.detect_and_raise_error(response)
Aug 29 03:44:33 hass hass[3535]:   File "/opt/srv/homeassistant/.virtualenvs/hass-py36/lib/python3.6/site-packages/fitbit/exceptions.py", line 82, in detect_and_raise_error
Aug 29 03:44:33 hass hass[3535]:     raise HTTPUnauthorized(response)
Aug 29 03:44:33 hass hass[3535]: fitbit.exceptions.HTTPUnauthorized: Access token expired: eyJhbGciOiJIUzI1NiJ9.eyJzdWIiOiI0SktIM1MiLCJhdWQiOiIyMjdWsecret. Visit https://dev.fitbit.com/docs/oauth2 for more information on the Fitbit Web API authorization process.

[tchellomello]

OK, after studying a little bit the python-fitbit the problem is that a refresh_cb constructor must be passed to the oauth client. So that is why the application currently just work while the token is valid.

More details at orcasgit/python-fitbit#119 (comment)

I'm checking how to implement it.

[tchellomello]

Ok, this PR will now fix the problem. We are now able to refresh the token on every HA restart or when the token gets expired. I tested it and it worked fine.

Basically what happens it that python-fitbit module requires an extra kwarg on the FitBit constructor called refresh_cb. The value should be a function that accepts one argument token.

The fix basically implements a lambda refresh_cb method as required by the Fitbit module to work, however the new token will be always saved manually on every update() call.

@pvizeli PR looks good now. I removed the WIP from the title.

Thanks!