Add new model directory to app.yaml.
Add new model directory to app.yaml.

Missed this in r178597.

TBR=abarth@chromium.org

Review URL: https://codereview.chromium.org/406973004

git-svn-id: bf5cd6ccde378db821296732a091cfbcf5285fbd@178598 bbb929c8-8fbe-4397-9dbb-9b2b20218538

axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk