Ran "2to3 -w -n -f except ./".

The scripts still work with Python 2.
There are no intended behaviour changes.

Bug: 942522
Change-Id: Ifa274cb83f74cfa8ce092fffbb88f3ab5309e72c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/1607841
Commit-Queue: Raul Tambre <raul@tambre.ee>
Auto-Submit: Raul Tambre <raul@tambre.ee>
Reviewed-by: Dirk Pranke <dpranke@chromium.org>