Add PROJECT to codereview.settings

This is needed once we move over to Chromium's
Rietveld instance at codereview.chromium.org.

BUG=3884
R=niklas.enbom@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/25129004

git-svn-id: http://webrtc.googlecode.com/svn/trunk@7681 4adac7df-926f-26a2-2b94-8c16560cd09d