Fix pylint E103 warning raised by usage of
self.__class__ to refer to the derived class
in super() methods.
self.__class__ is a reasonable first argument
to super() in any method of a class, as long
as the method is not going to be invoked in
derived classes.
Python3 removes this ambiguity by not requiring
arguments for the super() method.
[1] https://docs.pylint.org/en/1.6.0/features.html#id33
Change-Id: I6071b6cfd8cff2be3853d739f71b94da990cda97
fd23a6387c