setup/flake8: remove fixed E261

"E261: at least two spaces before inline comment" has been fixed
across the whole tree, so there is no need for an exception here.

Signed-off-by: Benjamin Tissoires <benjamin.tissoires@gmail.com>
3 jobs for master in 1 minute and 53 seconds (queued for 1 second)
Status Job ID Name Coverage
  Test
passed #761356
flake

00:01:47

passed #761357
install

00:01:47

passed #761358
install_no_man_pages

00:01:52