o Minor bugfixes (pluggable transports):
    - Enable the ExtORPortCookieAuthFile option, to allow changing the
      default location of the authentication token for the extended OR Port
      as used by sever-side pluggable transports. We had implemented this
      option before, but the code to make it settable had been omitted.
      Fixes bug 11635; bugfix on 0.2.5.1-alpha.