935ce8afdcaf0391d47407cb48c88725f6c6623c

It is too easy to forget to override isAuthSupported in download schemes that support but do not require authentication. Make it abstract so anyone adding a new download scheme has to make an explicit choice about whether it should show up on changes that are not world-readable. Change-Id: Ifbc70c0d3b6eea08ceee726317381cabd3892e03
Description
RETIRED, Gerrit as used by OpenStack