Is easier to configure experimental bots this way.

Bug: 643346
Change-Id: Idb6d3a68b02949dce71dbcba38e8ef756c467830
Reviewed-on: https://chromium-review.googlesource.com/981515
Commit-Queue: Edward Lesmes <ehmaldonado@chromium.org>
Reviewed-by: Robbie Iannucci <iannucci@chromium.org>