man page history cleanup

[ibotty]

> HISTORY
>      The tftpd utility appeared in 4.2BSD; the -s option was introduced
>      in DragonFly 2.2, the -u option was introduced in DragonFly 4.2,
>      and the -c option was introduced in DragonFly 4.3.
> 
> Presumably the result of a wholesale s/FreeBSD/DragonFly/g in the man
> pages.  I'm going to work through the man tree and fix these; depending
> on actual-work load, I should have a patch either in the next couple of
> days, or next week. ;)

considering what happened to microbsd.

i do not say, that we are equally bad, but falsify history is really up to
politicians not us.

just my 2¢.
~ibotty