Allow tabs since it's adhd coding convention.

BUG=None
TEST=ran hooks against changes in adhd

Change-Id: I9cec3fb477939632c5adc37064a3c80d450429f2
Reviewed-on: https://chromium-review.googlesource.com/741301


Commit-Ready: Chinyue Chen <chinyue@chromium.org>
Tested-by: Chinyue Chen <chinyue@chromium.org>
Reviewed-by: Mike Frysinger <vapier@chromium.org>