Update "p5-IO-Socket-INET6" package to version 2.67.

Update "p5-IO-Socket-INET6" package to version 2.67.
Changes since version 2.65:
- IO-Socket is doing some imports so we now do use IO::Socket ().
  - Fixed the rest of the imports.
- Thanks to LeoNerd
- Made the use Socket call import constants selectively, and not rely
  on @EXPORT's whims:
- http://www.cpantesters.org/cpan/report/d6e547be-19b5-11e0-bbdc-e5c0d6c987b5

This update stops warnings about re-defining "sockaddr_in6" produced
by e.g. "mrtg" or "spamassassin".