tor/changes/prettier-signature-log

  o Minor features
    - Make the formerly ugly "2 unknown, 7 missing key, 0 good, 0 bad,
      2 no signature, 4 required" messages easier to read, and make sure
      they get logged at the same severity as the messages explaining
      which keys are which.  Fixes bug 1290.
    - Don't warn when we have a consensus that we can't verify because
      of missing certificates, unless those certificates are ones
      that we have been trying and failing to download.  Fixes bug 1145.