dev-python: upgrade selenium to upstream

Upgrade the dev-python/selenium package to the latest version, which
must be done prior to upgrading the python eclasses, which do not accept
ebuilds using EAPI 4.

BUG=chromium:867070
TEST=`./update_chroot` and `./build_packages --board=chell` both work.

Change-Id: I6fe56e8f009c7b89ab8f3b2252e14f6c4439618f
Reviewed-on: https://chromium-review.googlesource.com/1162755
Commit-Ready: Alex Khouderchah <akhouderchah@chromium.org>
Tested-by: Alex Khouderchah <akhouderchah@chromium.org>
Reviewed-by: Mike Frysinger <vapier@chromium.org>
4 files changed