dpkg: ImportError: No module named seamicroclient.v2

When installing maas-region-controller, dpkg stops at the error below:

ImportError: No module named seamicroclient.v2
dpkg: error processing package maas-dns (--configure):
 subprocess installed post-installation script returned error exit status 1

python-seamicroclient is in the dependency of maas-cluster-controller but not in maas-region-controller.

ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: maas-region-controller 1.5.1+bzr2269-0ubuntu0.1
ProcVersionSignature: User Name 3.13.0-24.46-generic 3.13.9
Uname: Linux 3.13.0-24-generic x86_64
ApportVersion: 2.14.1-0ubuntu3
Architecture: amd64
Date: Sat May 31 06:14:23 2014
PackageArchitecture: all
ProcEnviron:
 TERM=screen-bce
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: maas
UpgradeStatus: No upgrade log present (probably fresh install)