buffering history text file writes

[Katsuhiro Kondou]

In article <Pine.SUN.4.20.0012261746440.23062-100000 at glas>,
	Ilya Etingof <ilya at glas.net> wrote;

} Although I have not yet noticed any problems while running hacked innd,
} I've not digged into innd code deeply enough to be certain that my hacks
} do not break anything to innd.

I think it's helpful for the server, unless the server runs
nnrpd(noreader in inn.conf is false) and overview data is
created(enableoverview is true).
-- 
Katsuhiro Kondou