Update to r39207:
Correct a few entries that were mistakenly changed which would adversely
affect users of 8.x and prior by noting separate rc.conf(5) entries for
8.x and earlier or 9.x and later.

Submitted by:	Bjoern Heidotting
Obtained from:	The FreeBSD German Documentation Project
Update to r40525:
- The nsupdate(8) man page no longer exists: nsupdate(1) replaces it. Change
the reference in the "network servers" Handbook chapter. [1]
- Add nsupdate(1) to the man page references file, without removing the old
one so that translations don't break.

Submitted by:	Bjoern Heidotting
Obtained from:	The FreeBSD German Documentation Project