package spamassassin 3.4.0-1ubuntu1 failed to install/upgrade: set: Illegal option -o postfix

Our configuration files may be obsolete.
Also there is a warning about file permissions in /var/lib/spamassassin (?) that I haven't checked yet.

ProblemType: Package
DistroRelease: Ubuntu 14.04
Package: spamassassin 3.4.0-1ubuntu1
ProcVersionSignature: Ubuntu 3.11.0-12.19-generic 3.11.3
Uname: Linux 3.11.0-12-generic x86_64
ApportVersion: 2.14.1-0ubuntu3
Architecture: amd64
Date: Fri Sep 19 11:03:40 2014
DuplicateSignature: package:spamassassin:3.4.0-1ubuntu1:subprocess installed post-installation script returned error exit status 2
ErrorMessage: subprocess installed post-installation script returned error exit status 2
InstallationDate: Installed on 2012-12-11 (647 days ago)
InstallationMedia: Ubuntu-Server 12.10 "Quantal Quetzal" - Release amd64 (20121017.2)
PackageArchitecture: all
SourcePackage: spamassassin
Title: package spamassassin 3.4.0-1ubuntu1 failed to install/upgrade: subprocess installed post-installation script returned error exit status 2
UpgradeStatus: Upgraded to trusty on 2014-09-19 (0 days ago)
mtime.conffile..etc.default.spamassassin: 2014-02-27T15:00:48.388069
mtime.conffile..etc.spamassassin.init.pre: 2014-05-16T14:53:54.726876
mtime.conffile..etc.spamassassin.local.cf: 2014-05-16T14:53:54.742876

Adding new user `debian-spamd' (UID 124) with group `debian-spamd' ...^M
The home directory `/var/lib/spamassassin' already exists. Not copying from `/etc/skel'.^M
adduser: Warning: The home directory `/var/lib/spamassassin' does not belong to the user you are currently creating.^\
M
-su: 5: set: Illegal option -o posix^M