Remove the OWNERS that no longer work on the project.

Remove jcivelli@, and nileshagrawal@ who no longer work
on Chrome for Android.

Review URL: https://chromiumcodereview.appspot.com/18178014

git-svn-id: http://src.chromium.org/chrome/trunk/src/testing@209531 4ff67af0-8c30-449e-8e8b-ad334ec8d88c