Revert app.yaml change from https://codereview.chromium.org/579773002/
Revert app.yaml change from https://codereview.chromium.org/579773002/

BUG=
TBR=jrobbins@chromium.org

Review URL: https://codereview.chromium.org/612853002

nicko96/Chrome-Infra,nicko96/Chrome-Infra,nicko96/Chrome-Infra,nicko96/Chrome-Infra,nicko96/Chrome-Infra