depends on libowfat which is in community

Following rules have been applied:
- script starts with shebang !#/bin/sh followed by blank line,
- script ends with exit 0 prepended by blank line,
- only stderr of adduser, addgroup or passwd is redirected to /dev/null,
- getent passwd/group instances has been removed,
- manual checking of file and group existence has been removed,
- `|| true` instances has been removed.

Comments and line wrapping have been preserved.

This way we can avoid ugly default:

    Linux user,,,

It's only for consistency and to ease spotting lack of it.

fixes #190

we dont want change permissions on /var/empty

an open and free bittorrent tracker
http://erdgeist.org/arts/software/opentracker/