Bug#716723: sasl2-bin: subprocess installed post-installation script returned error exit status 1

[Johannes Schlumberger]

Package: sasl2-bin
Version: 2.1.25.dfsg1-6+deb7u1
Severity: important

Dear Maintainer,
this one has been going on for a while (2 years+ I would say) during a
dist-upgrade I saw this message box for the first time:
                         Configuring sasl2-bin
Failed to upgrade /etc/sasldb2
The /etc/sasldb2 file could not be upgraded to the new database format.
This is a fatal error and will cause the package installation to fail.
The configuration process will attempt to restore the backup of this file to its original location.
Please eliminate all possible reasons that might lead to this failure, then try to configure this package again.
                                                     <Ok>

As far as I can tell the operation of my mailserver that uses SASL for
authentication has not been influenced by this bug.
It is now one or two Debian Versions later and the error has not been resolved.
please let me know if you need more information.
	thanks,
		Johannes

-- System Information:
Debian Release: 7.1
  APT prefers stable
  APT policy: (500, 'stable')
Architecture: i386 (i686)

Kernel: Linux 3.2.0-4-686-pae (SMP w/2 CPU cores)
Locale: LANG=en_US.ISO-8859-15, LC_CTYPE=en_US.ISO-8859-15 (charmap=ISO-8859-15)
Shell: /bin/sh linked to /bin/bash

Versions of packages sasl2-bin depends on:
ii  db-util                5.1.6
ii  debconf [debconf-2.0]  1.5.49
ii  libc6                  2.13-38
ii  libcomerr2             1.42.5-1.1
ii  libdb5.1               5.1.29-5
ii  libgssapi-krb5-2       1.10.1+dfsg-5+deb7u1
ii  libk5crypto3           1.10.1+dfsg-5+deb7u1
ii  libkrb5-3              1.10.1+dfsg-5+deb7u1
ii  libldap-2.4-2          2.4.31-1+nmu2
ii  libpam0g               1.1.3-7.1
ii  libsasl2-2             2.1.25.dfsg1-6+deb7u1
ii  libssl1.0.0            1.0.1e-2
ii  lsb-base               4.1+Debian8+deb7u1

sasl2-bin recommends no packages.

sasl2-bin suggests no packages.

-- debconf information:
* cyrus-sasl2/upgrade-sasldb2-failed:
  cyrus-sasl2/backup-sasldb2: /var/backups/sasldb2.bak
  cyrus-sasl2/upgrade-sasldb2-backup-failed:
  cyrus-sasl2/purge-sasldb2: false