Bug#508165: exim4-config: exim4 install fails with dpkg-statoverride: non-existing group Debian-exim

[Will Hargrave]

Package: exim4-config
Version: 4.69-9
Severity: grave
Justification: renders package unusable

On attempting to install exim (apt-get install exim4) fails with:

======
Setting up exim4-config (4.69-9) ...
/usr/sbin/dpkg-statoverride: non-existing group Debian-exim

Usage: dpkg-statoverride [<option> ...] <command>

Commands:
  --add <owner> <group> <mode> <file>
                           add a new entry into the database.
  --remove <file>          remove file from the database.
  --list [<glob-pattern>]  list current overrides in the database.

Options:
  --admindir <directory>   set the directory with the statoverride file.
  --update                 immediately update file permissions.
  --force                  force an action even if a sanity check fails.
  --quiet                  quiet operation, minimal output.
  --help                   show this help message.
  --version                show the version.
======

AFAIK this machine has never had exim4 installed. 

-- Package-specific info:
mailname:mon0.lonap.net

-- System Information:
Debian Release: lenny/sid
  APT prefers testing
  APT policy: (500, 'testing')
Architecture: i386 (i686)

Kernel: Linux 2.6.18-6-xen-vserver-686 (SMP w/1 CPU core)
Locale: LANG=en_GB.UTF-8, LC_CTYPE=en_GB.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/bash

Versions of packages exim4-config depends on:
ii  adduser                       3.110      add and remove users and groups
ii  debconf [debconf-2.0]         1.5.22     Debian configuration management sy

exim4-config recommends no packages.

exim4-config suggests no packages.

-- debconf information:
  exim4/dc_other_hostnames: mon0.lonap.net
  exim4/dc_eximconfig_configtype: local delivery only; not on a network
  exim4/no_config: true
  exim4/hide_mailname:
  exim4/dc_postmaster:
  exim4/dc_smarthost:
  exim4/dc_relay_domains:
  exim4/dc_relay_nets:
  exim4/mailname: mon0.lonap.net
  exim4/dc_readhost:
  exim4/use_split_config: false
  exim4/exim4-config-title:
  exim4/dc_localdelivery: mbox format in /var/mail/
  exim4/dc_local_interfaces: 127.0.0.1
  exim4/dc_minimaldns: false