o Major bugfixes (directory authority):
    - When deciding whether we have just found a router to be reachable,
      do not penalize it for not having performed an Ed25519 link handshake
      if it does not claim to support an Ed25519 handshake. Previously,
      we would treat such relays as non-running.
      Fixes bug 21107; bugfix on 0.2.3.1-alpha.