How to avoid reinstalling deliberately deleted config files on upgrade

[Richard Siddall]

I'm packaging a system that uses the presence of configuration files to 
set some options: the option is on if the file is present, and off if 
the file is missing.

The problem I've run into (obviously) is that when I upgrade the RPM to 
a newer version, rpm reinstalls all the deliberately deleted config files.

I can't think of a way to stop rpm from doing this.  Does anyone have 
any suggestions?

Regards,

	Richard Siddall