file does not exist on Python 3.

Change-Id: I9392fd797b730784cff4d1144c5a3ab1027c7dd8
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/2086493Reviewed-by: Josip Sokcevic <sokcevic@google.com>
Commit-Queue: Edward Lesmes <ehmaldonado@chromium.org>