This will help remove confusion when depot_tools' recipes.py
ends up in PATH.

BUG=699120

Change-Id: Id4c21b0cc6bb022ea2c21145abe76bebb0a8d9c1
Reviewed-on: https://chromium-review.googlesource.com/458430
Commit-Queue: Paweł Hajdan Jr. <phajdan.jr@chromium.org>
Reviewed-by: Robbie Iannucci <iannucci@chromium.org>