This makes it possible to run hooks properly
in flattened DEPS.

Bug: 570091
Change-Id: If8175a57ebe8f607bd4ac83d4a26dcc4cc18165c
Reviewed-on: https://chromium-review.googlesource.com/535476Reviewed-by: Andrii Shyshkalov <tandrii@chromium.org>
Commit-Queue: Paweł Hajdan Jr. <phajdan.jr@chromium.org>