o Major bugfixes (directory authorities):
    - Stop allowing 0 as a port in exit policy lines. We had put in some
      secondary checks to make sure exit policy ports weren't out of
      the expected range, but one of those checks accidentally allowed
      us to parse the port "0" as equivalent to the port range "1-0",
      which triggered an assert when generating a networkstatus vote
      (on v3 directory authorities) or a networkstatus document (on the
      bridge authority). Fixes bug 41292; bugfix on 0.1.2.5-alpha.