CONTRIBUTORS: add Jonathan Feinberg (Google CLA)
CONTRIBUTORS: add Jonathan Feinberg (Google CLA)

R=golang-dev, bradfitz
CC=golang-dev
http://codereview.appspot.com/6553067
abustany/go,abustany/go,abustany/go,abustany/go,abustany/go,abustany/go,abustany/go