[lint] Fix pylint v2.6.0 new checks

http://pylint.pycqa.org/en/latest/whatsnew/2.6.html#new-checkers
http://pylint.pycqa.org/en/latest/technical_reference/features.html

raise-missing-from (W0707)
https://stackoverflow.com/a/6246394
https://www.python.org/dev/peps/pep-3134/

R1725: Consider using Python 3 style super() without arguments