postrm is in fai-client 3.4.8ubuntu5.
This file is a maintainer script. It is executed when installing (*inst) or removing (*rm) the package.
The actual contents of the file can be viewed below.
| 1 2 3 4 5 6 7 8 9 10 11 12 13 | #! /bin/sh
set -e
case "$1" in
    purge)
	rm -rf /var/run/fai
        ;;
esac
exit 0
 |