No RAIDframe on OpenBSD anymore

[Klemens Nanni <kn%openbsd.org@localhost>]

https://netbsd.org/docs/guide/en/chap-rf.html#chap-rf-intro-about
says
  [...]
  RAIDframe can also be found in OpenBSD and older versions of FreeBSD.
  [...]

but https://www.openbsd.org/52.html from 2012 says
  Removed the raid(4) RAIDframe driver and its corresponding raidctl(8)
  utility. RAIDframe has been superseded by softraid(4).

See
  https://man.openbsd.org/OpenBSD-5.1/raid.4
  https://man.openbsd.org/softraid.4