Remove invalid rwho(1)/ruptime(1)/rwhod(8) deprecation notice.

[jlh]

Summary

rwho(1)/ruptime(1)/rwhod(8) were initially thought to belong to rcmds,
but peter@ pointed out they weren't:
https://reviews.freebsd.org/rS322029

[bcr]

This is a content change, so you need to bump the document dates of these man pages (although it is just a revert).

[jlh]

Update the date of the manpages, as requested by bcr@.

[jlh]

I submitted the changes in https://svnweb.freebsd.org/base?view=revision&revision=325049