More pylint 2 fixes (#15565)

## Description:

More fixes flagged by pylint 2 that don't hurt to have before the actual pylint 2 upgrade (which I'll submit soon).

## Checklist:
  - [ ] The code change is tested and works locally.
  - [x] Local tests pass with `tox`. **Your PR cannot be merged unless tests pass**

homeassistant/components/pilight.py

@@ -118,7 +118,7 @@ def setup(hass, config):
     return True
 
 
-class CallRateDelayThrottle(object):
+class CallRateDelayThrottle:
     """Helper class to provide service call rate throttling.
 
     This class provides a decorator to decorate service methods that need