Upgrading from 14.10 to 15.04 - could not calculate the upgrade

[Marcel Beerli]

My prev. Bug report
 [Bug 1458145] Re: Upgrading from 14.10 to 15.04 - could not calculate the upgrade

*** This bug is a duplicate of bug 1069133 ***
    https://bugs.launchpad.net/bugs/1069133

Reviewing the files from your upgrade attempt you seem to have enabled
the xorg-edgers-ppa. This will prevent the upgrade as that PPA contains
different versions of packages essential to Ubuntu. The page,
https://launchpad.net/~xorg-edgers/+archive/ppa, contains details on to
how to revert to the official Xorg packages. Thanks.

So I removed the xorg-edgers with

> sudo ppa-purge xorg-edgers

Restarted the upgrade, same warning again.

ProblemType: Bug
DistroRelease: Ubuntu 14.10
Package: ubuntu-release-upgrader-core 1:14.10.10
ProcVersionSignature: Ubuntu 3.16.0-38.52-generic 3.16.7-ckt10
Uname: Linux 3.16.0-38-generic x86_64
NonfreeKernelModules: nvidia
ApportVersion: 2.14.7-0ubuntu8.5
Architecture: amd64
CrashDB: ubuntu
CurrentDesktop: Unity
Date: Sat May 23 15:56:09 2015
InstallationDate: Installed on 2014-04-23 (394 days ago)
InstallationMedia: Ubuntu 14.04 LTS "Trusty Tahr" - Release amd64 (20140417)
PackageArchitecture: all
SourcePackage: ubuntu-release-upgrader
UpgradeStatus: Upgraded to utopic on 2015-05-23 (0 days ago)
VarLogDistupgradeTermlog:

[Ubuntu Foundations Team Bug Bot (crichton)]

Reviewing the files from your upgrade attempt you seem to have enabled the xorg-edgers-ppa. This will prevent the upgrade as that PPA contains different versions of packages essential to Ubuntu. The page, https://launchpad.net/~xorg-edgers/+archive/ppa, contains details on to how to revert to the official Xorg packages. Thanks.

[This is an automated message. I apologize if it reached you inappropriately; please just reply to this message indicating so.]

[Ubuntu Foundations Team Bug Bot (crichton)]

Thank you for taking the time to report this bug and helping to make Ubuntu better. This particular bug has already been reported and is a duplicate of bug 1069133, so it is being marked as such. Please look at the other bug report to see if there is any missing information that you can provide, or to see if there is a workaround for the bug. Additionally, any further discussion regarding the bug should occur in the other report. Please continue to report any other bugs you may find.
[This is an automated message. I apologize if it reached you inappropriately; please just reply to this message indicating so.]