Make Throttle async aware

[balloob]

Description:

Throttle was not async aware. With coroutines these errors got swallowed but with async/await they surfaced, which is good as now we have been able to squash a bunch of bugs.

Found all instances where we combined an @async.coroutine with a @Throttle. I've converted them all to async/await and also fixed the Throttle decorator.

Found all instances with:

git grep -A3 -B3 Throttle | grep coroutine

Related issue (if applicable): fixes #13012

Checklist:

• The code change is tested and works locally.
• Local tests pass with tox. Your PR cannot be merged unless tests pass

If user exposed functionality or configuration variables are added/changed:

• Documentation added/updated in home-assistant.github.io

If the code communicates with devices, web services, or third-party tools:

• New dependencies have been added to the REQUIREMENTS variable (example).
• New dependencies are only imported inside functions that use them (example).
• New dependencies have been added to requirements_all.txt by running script/gen_requirements_all.py.
• New files were added to .coveragerc.

If the code does not interact with devices:

• Tests have been added to verify that the new code works.

[balloob]

Removed this type error because that would happen if Throttle was returning None…

[DavidFW1960]

Heres the sabnzdb log (I'm home now and I can paste it - not on iPad now)

Sat Mar 10 2018 14:27:14 GMT+1100 (Local Daylight Time)

Error while setting up platform sabnzbd
Traceback (most recent call last):
  File "/usr/lib/python3.6/site-packages/homeassistant/helpers/entity_platform.py", line 82, in async_setup
    SLOW_SETUP_MAX_WAIT, loop=hass.loop)
  File "/usr/lib/python3.6/asyncio/tasks.py", line 358, in wait_for
    return fut.result()
  File "/usr/lib/python3.6/asyncio/futures.py", line 245, in result
    raise self._exception
  File "/usr/lib/python3.6/asyncio/tasks.py", line 180, in _step
    result = coro.send(None)
  File "/usr/lib/python3.6/site-packages/homeassistant/components/sensor/sabnzbd.py", line 153, in async_setup_platform
    if not (yield from async_check_sabnzbd(SabnzbdApi, base_url, api_key)):
  File "/usr/lib/python3.6/site-packages/homeassistant/components/sensor/sabnzbd.py", line 62, in async_check_sabnzbd
    yield from sab_api.check_available()
  File "/usr/lib/python3.6/site-packages/pysabnzbd/__init__.py", line 43, in check_available
    with aiohttp.ClientSession() as session:
  File "/usr/lib/python3.6/site-packages/aiohttp/client.py", line 742, in __enter__
    raise TypeError("Use async with instead")
TypeError: Use async with instead

[balloob]

sabnzdb has been fixed in #13042

[thomasvt1]

I think the Tado component suffers from the same issue (Also like #13012)

2018-03-11 00:56:28 ERROR (MainThread) [homeassistant.core] Error doing job: Task exception was never retrieved
Traceback (most recent call last):
  File "/usr/local/lib/python3.6/asyncio/tasks.py", line 180, in _step
    result = coro.send(None)
  File "/usr/local/lib/python3.6/site-packages/homeassistant/components/device_tracker/__init__.py", line 738, in async_device_tracker_scan
    found_devices = yield from scanner.async_scan_devices()
  File "/usr/local/lib/python3.6/site-packages/homeassistant/components/device_tracker/tado.py", line 81, in async_scan_devices
    yield from info
  File "/usr/local/lib/python3.6/site-packages/homeassistant/components/device_tracker/tado.py", line 121, in _update_info
    tado_json = yield from response.json()
TypeError: cannot 'yield from' a coroutine object in a non-coroutine generator

[balloob]

@thomasvt1 thanks for the report, opened #13078 with a fix