tor/changes/bug21394

  o Major bugfixes (Exit nodes):
    - Fix an issue causing high-bandwidth exit nodes to fail a majority
      or all of their DNS requests, making them basically unsuitable for
      regular usage in Tor circuits. The problem is related to
      libevent's DNS handling, but we can work around it in Tor. Fixes
      bugs 21394 and 18580; bugfix on 0.1.2.2-alpha which introduced
      eventdns. Credit goes to Dhalgren for identifying and finding a
      workaround to this bug and to gamambel, arthuredelstein and
      arma in helping to track it down and analyze it.