runtests: catch EPROTONOSUPPORT in checkportisavailable This is a follow-up of "runtests: check ports on IPv6 address". On some platforms, "socket.AF_INET6" exists while that does not necessarily mean the platform support IPv6 - when initializing a socket using "socket.socket", it could fail with EPROTONOSUPPORT. So treat that as "Port unavailable".

#require docutils gettext

  $ $TESTDIR/check-gendoc fr
  checking for parse errors