Comment 2 for bug 1672469

From the log file:
ERROR:root:failed to mark 'ubuntu-desktop' for install (E:Unable to correct problems, you have held broken packages.)
ERROR:root:Unauthenticated packages found: 'aptdaemon gir1.2-packagekitglib-1.0 libpackagekit-glib2-18 libqt4-dbus libqt4-declarative libqt4-network libqt4-opengl libqt4-script libqt4-sql libqt4-sql-sqlite libqt4-xml libqt4-xmlpatterns libqt5core5a libqt5dbus5 libqt5gui5 libqt5multimedia5 libqt5network5 libqt5opengl5 libqt5printsupport5 libqt5qml5 libqt5quick5 libqt5quicktest5 libqt5sql5 libqt5sql5-sqlite libqt5svg5 libqt5test5 libqt5webkit5 libqt5widgets5 libqt5xml5 libqtcore4 libqtdbus4 libqtgui4 python3-aptdaemon python3-aptdaemon.gtk3widgets qdbus qml-module-qtgraphicaleffects qml-module-qtquick-window2 qml-module-qtquick2 qml-module-qttest qmlscene qtchooser qtdeclarative5-dev-tools'