MFC r274364:

  Add baud rate support to telnet(1)

  This implements part of RFC-2217

  It's based off a patch originally written by Sujal Patel at Isilon, and
  contributions from other Isilon employees.

  PR: [[ https://bugs.freebsd.org/173728 | 173728 ]]
  Phabric: D995
  Reviewed by: markj, markm
  Sponsored by: EMC / Isilon Storage Division

MFC r274365:

  Revert WiP to contrib/tzcode accidentally committed with r274364