doc: Clarify some BosConfig.new text

It is not always clear to users whether BosConfig.new is noticed
during an automatic restart, or if it requires stopping and starting
the bosserver. Slightly reword the relevant text and add a small note
that a "general restart" does cause BosConfig.new to be noticed, so
this is explicitly clear.

Reviewed-on: http://gerrit.openafs.org/11076
Reviewed-by: Andrew Deason <adeason@sinenomine.net>
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Jeffrey Altman <jaltman@your-file-system.com>
(cherry picked from commit 3946b50a7ecdfd34681ab471863929b2f82aff4b)

Change-Id: Ia630aec6ef5259fc3c3fd531fdf8fda8a4152c54
Reviewed-on: http://gerrit.openafs.org/11216
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Ken Dreyer <ktdreyer@ktdreyer.com>
Reviewed-by: Andrew Deason <adeason@sinenomine.net>
Reviewed-by: Stephan Wiesand <stephan.wiesand@desy.de>