do-release-upgrade fails.

[defaria]

This is what I saw:

Checking package manager
Reading package lists... Done
Building dependency tree
Reading state information... Done
Building data structures... Done

Calculating the changes

Calculating the changes

Could not calculate the upgrade

An unresolvable problem occurred while calculating the upgrade.

This can be caused by:
* Upgrading to a pre-release version of Ubuntu
* Running the current pre-release version of Ubuntu
* Unofficial software packages not provided by Ubuntu

If none of this applies, then please report this bug using the
command 'ubuntu-bug ubuntu-release-upgrader-core' in a terminal.

Restoring original system state

Aborting
Reading package lists... Done
Building dependency tree
Reading state information... Done
Building data structures... Done

ProblemType: Bug
DistroRelease: Ubuntu 14.10
Package: ubuntu-release-upgrader-core 1:14.10.10
ProcVersionSignature: Ubuntu 3.16.0-39.53-generic 3.16.7-ckt11
Uname: Linux 3.16.0-39-generic x86_64
ApportVersion: 2.14.7-0ubuntu8.5
Architecture: amd64
CrashDB: ubuntu
Date: Mon Jun 15 12:14:56 2015
InstallationDate: Installed on 2012-10-05 (982 days ago)
InstallationMedia: Ubuntu 12.04.1 LTS "Precise Pangolin" - Release amd64 (20120823.1)
PackageArchitecture: all
ProcEnviron:
 LANGUAGE=en_US
 TERM=xterm
 PATH=(custom, no user)
 LANG=C
 SHELL=/bin/bash
SourcePackage: ubuntu-release-upgrader
UpgradeStatus: Upgraded to utopic on 2015-06-15 (0 days ago)