Root file system not umounted, polkitd does not terminate at computer shutdown

Noticed that the machine always checks the root filesystem after booting. Noticed the "mount / busy" message during shutdown.

Description: Ubuntu 12.04.1 LTS
Release: 12.04

policykit-1:
  Installed: 0.104-1ubuntu1
  Candidate: 0.104-1ubuntu1
  Version table:
 *** 0.104-1ubuntu1 0
        500 http://de.archive.ubuntu.com/ubuntu/ precise-updates/main amd64 Packages
        100 /var/lib/dpkg/status
     0.104-1 0
        500 http://de.archive.ubuntu.com/ubuntu/ precise/main amd64 Packages

ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: policykit-1 0.104-1ubuntu1
Uname: Linux 3.2.36-030236-generic x86_64
ApportVersion: 2.0.1-0ubuntu17.1
Architecture: amd64
Date: Sun Jan 13 18:50:59 2013
ExecutablePath: /usr/lib/policykit-1/polkitd
MarkForUpload: True
OmitPids: 2497 1423 2497 1423 1308 3330 1247 1280 1174 3460 986 1338 1303 1308 3330 1247 1280 1174 3460 986 1338 1303
ProcCmdline: /usr/lib/policykit-1/polkitd --no-debug
ProcEnviron:

SourcePackage: policykit-1
Title: polkitd does not terminate at computer shutdown
UpgradeStatus: No upgrade log present (probably fresh install)