python: support pylint 2.16

python: support pylint 2.16

Pylint 2.16 adds a few new checks that cause the optional check-tox CI
job to fail.

1. The superfluous-parens check seems to be a bit more aggressive,
2. broad-exception-raised is new; it discourages "raise Exception".

Fix these minor issues and turn the lights green.

Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Beraldo Leal <bleal@redhat.com>
Message-id: 20230210003147.1309376-2-jsnow@redhat.com
Signed-off-by: John Snow <jsnow@redhat.com>