Drop pylint due to the huge amount of false positives

Given that pylint is raising a lot of false positives
and that we have alternative static code checkers,
we decided to remove pylint from the tox envlist.

This patch also fix some pylint true positives
and cleans up the disabled pylint tests in the codebase.

Change-Id: I6fb4b9b4c80af452796032736e39ef064b9bcd03
Closes-Bug: #1297994