Downside: the script now requires "-u user@chromium.org" or it results
in "error: USER is not set, please use -u".

Bug: 904604
Change-Id: I241ad440d0cf1a495ce6f57e48ed49d9d90a49d9
Reviewed-on: https://chromium-review.googlesource.com/c/1442851Reviewed-by: Robbie Iannucci <iannucci@chromium.org>
Commit-Queue: Gabriel Charette <gab@chromium.org>