Various fixes for inetd's TCP Wrappers support:

Various fixes for inetd's TCP Wrappers support:

	1) Handle forking and non-forking internal services correctly.
	   Turn on wrapping for internal services because it works now.
	2) Preserve server names for each service on HUP.
	3) Honour hosts_options(5) severity option.
	4) Add IMPLEMENTATION NOTES section to clarify TCP Wrappers
	   usage and limitations.

This change may cause previously allowed builtin services (e.g. daytime)
to be denied in existing configurations.

PR:	12097
Reviewed by:	markm
1)
Reported by:	Pierre Beyssac <pb@fasterix.freenix.org>
2)
Submitted by:	Masachika ISHIZUKA <ishizuka@ish.org>
3)
Submitted by:	David Malone <dwmalone@maths.tcd.ie>