tor/changes/1324-fetch-from-v3-not-v2

  o Major bugfixes:
    - Directory mirrors were fetching relay descriptors only from v2
      directory authorities, rather than v3 authorities like they should.
      Only 2 v2 authorities remain (compared to 7 v3 authorities), leading
      to a serious bottleneck. Bugfix on 0.2.0.9-alpha. Fixes bug 1324.