o Security fixes:

    - Don't send TLS certificate chains on outgoing OR connections
      from clients and bridges.  Previously, each client or bridge
      would use a single cert chain for all outgoing OR connections
      for up to 24 hours, which allowed any relay connected to by a
      client or bridge to determine which entry guards it is using.
      This is a potential user-tracing bug for *all* users; everyone
      who uses Tor's client or hidden service functionality should
      upgrade.  Fixes CVE-2011-2768.  Bugfix on FIXME; found by
      frosty_un.