A CL might delete an OWNERS file which we still need to read for the OWNERS
check.

BUG=778870
R=agable@chromium.org

Change-Id: I25636ff36228a1afb3c10edf5c2419773a4d057e
Reviewed-on: https://chromium-review.googlesource.com/754623Reviewed-by: Aaron Gable <agable@chromium.org>
Commit-Queue: Jochen Eisinger <jochen@chromium.org>