package sa-compile 3.4.0-3 failed to install/upgrade: subprocess installed post-installation script returned error exit status 2

[Joaquim Mariano]

Since I've upgraded from 14.04 to 14.10, an error related to sa-compile occurs during most of my updates and package installations.

Acer Aspire One 722
OS: Ubuntu 14.10 with Unity
CPU: AMD C-60 APU with Radeon HD Graphics
RAM: 2 GB DDR3 SDRAM
Storage: 500 GB HDD Seagate

ProblemType: Package
DistroRelease: Ubuntu 14.10
Package: sa-compile 3.4.0-3
ProcVersionSignature: Ubuntu 3.16.0-24.32-generic 3.16.4
Uname: Linux 3.16.0-24-generic x86_64
ApportVersion: 2.14.7-0ubuntu8
Architecture: amd64
Date: Wed Nov 5 02:41:09 2014
DpkgHistoryLog:
 Start-Date: 2014-11-05 02:40:29
 Commandline: aptdaemon role='role-commit-packages' sender=':1.97'
 Upgrade: ruby2.1:amd64 (2.1.2-2ubuntu1, 2.1.2-2ubuntu1.1), libruby2.1:amd64 (2.1.2-2ubuntu1, 2.1.2-2ubuntu1.1), ruby2.1-dev:amd64 (2.1.2-2ubuntu1, 2.1.2-2ubuntu1.1)
DuplicateSignature: package:sa-compile:3.4.0-3:subprocess installed post-installation script returned error exit status 2
ErrorMessage: subprocess installed post-installation script returned error exit status 2
InstallationDate: Installed on 2013-05-14 (540 days ago)
InstallationMedia: Ubuntu 13.04 "Raring Ringtail" - Release amd64 (20130424)
PackageArchitecture: all
SourcePackage: spamassassin
Title: package sa-compile 3.4.0-3 failed to install/upgrade: subprocess installed post-installation script returned error exit status 2
UpgradeStatus: Upgraded to utopic on 2014-10-24 (12 days ago)

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Bryce Harrington (bryce)]

DpkgTerminalLog.txt shows:
Running sa-compile (may take a long time)
sa-compile: cannot write to /var/lib/spamassassin/compiled/5.020/3.004000, aborting

The logs don't reveal much beyond that, perhaps it was /var mounted r-o or something?

I'm closing the bug out since it's not actionable as-is, and is against an old version of Ubuntu. If the issue can be reproduced on a newer version, please re-file.