The release includes its own check for delayed string interpolation for
log messages, so we can now remove our own check for the same thing. The
check is off-by-default, so we need to explicitly enable it. Sadly,
select= directive in tox.ini is broken [1] so we need to enable the
check with flake8 argument instead.
[1] https://github.com/PyCQA/pycodestyle/issues/390
Change-Id: Idc6b8e5b1cb594e130d4cc0cbcfffd362f9ab86a
Ihar Hrachyshka
4e25ba840a