Cannot shutdown, when more than one desktop user is created

Binary package hint: indicator-applet

On Lucid RC: after upgrading the system from Karmic, I cannot shutdown anymore easily. There is a PolicyKit authentication dialog:

"System prevents stopping the system when other users are logged in."
  org.freedesktop.consolekit.system.stop-multiple-users

The problem is... I'm the only user logged in the system. If I do who from the command line, I get:

> who
ludo tty8 2010-04-23 21:45 (:0)
ludo pts/0 2010-04-23 21:47 (:0.0)
ludo pts/1 2010-04-23 22:03 (:0.0)

It looks like policyKit is not able to recognize that the same user is logged multiple times.
I have no running applications, other than the terminal.

This bug seems related to #485681
---
Architecture: amd64
DistroRelease: Ubuntu 10.04
InstallationMedia: Ubuntu 9.10 "Karmic Koala" - Release amd64 (20091027)
Package: indicator-applet 0.3.6-0ubuntu2
PackageArchitecture: amd64
ProcEnviron:
 LANGUAGE=en_GB.utf8
 PATH=(custom, user)
 LANG=en_GB.utf8
 SHELL=/bin/bash
ProcVersionSignature: Ubuntu 2.6.32-21.32-generic 2.6.32.11+drm33.2
Tags: lucid
Uname: Linux 2.6.32-21-generic x86_64
UserGroups: adm admin audio cdrom dialout fax fuse lpadmin netdev plugdev sambashare tape users video