Comment 2 for bug 1670291

This does not require landscape-client. It can be reproduced via:

 * Install machine with 14.04.5 and fully upgrade it.
 * Execute 'do-release-upgrade' to upgrade to 16.04.
 * When the upgrade is finished, exit the release upgrade tool (do not allow the tool to reset the system).
 * Manually attempt to reboot the system with "sudo /sbin/shutdown -r"

The machine will not reboot and the shutdown command will exit with:
Failed to set wall message, ignoring: Method "SetWallMessage" with signature "sb" on interface "org.freedesktop.login1.Manager" doesn't exist
Failed to call ScheduleShutdown in logind, proceeding with immediate shutdown: Method "ScheduleShutdown" with signature "st" on interface "org.freedesktop.login1.Manager" doesn't exist

/var/log/* logs are attached.