logging.StreamHandler should call super().__init__()

[ulda]

logging.StreamHandler inherits from logging.Handler but does not call super().init()
so it misses to initialize level and formatter instance variables

by the way, logging.Handler should initialize formatter to a working formatter, not None.
e.g. if you create and add a new StreamHandler, it has no formatter set by default and any logging will generate an exception.

[colin-nolan]

I also encountered this issue, and have added a PR to fix in #710.