install fails with apparmor disabled

Boot a precise instance with kernel option 'apparmor=0'
Install maas-dhcp
ubuntu@ubuntu:~$ sudo apt-get install -y maas-dhcp
Setting up maas-dhcp (1.2+bzr1373+dfsg-0ubuntu1~12.04.1) ...
Warning: unable to find a suitable fs in /proc/mounts, is it mounted?
Use --subdomainfs to override.
dpkg: error processing maas-dhcp (--configure):
 subprocess installed post-installation script returned error exit status 1
dpkg: dependency problems prevent configuration of maas-dns:
 maas-dns depends on maas-dhcp (= 1.2+bzr1373+dfsg-0ubuntu1~12.04.1); however:
  Package maas-dhcp is not configured yet.
dpkg: error processing maas-dns (--configure):
 dependency problems - leaving unconfigured

Looks like apparmor should not be called in /var/lib/dpkg/info/maas-dhcp.postinst
and /var/lib/dpkg/info/maas-dhcp.postrm when apparmor is disabled.

Workaround
Boot the machine with apparmor enabled.

Package info

ubuntu@ubuntu:~$ sudo dpkg -l maas-dhcp
Desired=Unknown/Install/Remove/Purge/Hold
| Status=Not/Inst/Conf-files/Unpacked/halF-conf/Half-inst/trig-aWait/Trig-pend
|/ Err?=(none)/Reinst-required (Status,Err: uppercase=bad)
||/ Name Version Description
+++-=================================-=================================-==================================================================================
ii maas-dhcp 1.2+bzr1373+dfsg-0ubuntu1~12.04.1 Ubuntu MAAS Server - DHCP Configuration (meta-package)
ubuntu@ubuntu:~$
ubuntu@ubuntu:~$ uname -r
3.2.0-48-generic
ubuntu@ubuntu:~$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 12.04.2 LTS
Release: 12.04
Codename: precise