One more clue: In /var/log/dist-upgrade/main.log, I see the message:
2015-09-08 11:33:49,918 ERROR Dist-upgrade failed: 'E:Error, pkgProblemResolver::Resolve generated breaks, this may be caused by held packages.'
One more clue: In /var/log/ dist-upgrade/ main.log, I see the message:
2015-09-08 11:33:49,918 ERROR Dist-upgrade failed: 'E:Error, pkgProblemResol ver::Resolve generated breaks, this may be caused by held packages.'