This is created for the external gsutil since r293320, and was creating
needless churn in presubmit tests when it is present.

R=pgervais@chromium.org,hinoka@google.com
BUG=434422

Review URL: https://codereview.chromium.org/831913003

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@293574 0039d316-1c4b-4281-b951-d872f2087c98