Comment 6 for bug 1130809

I've been looking into this bug, here's the full environment as passed to lxc-ls:
SUDO_GID=200512
MAIL=/var/mail/root
USER=root
LANGUAGE=en_CA:en
HOME=/root
SUDO_UID=201105
LOGNAME=root
USERNAME=root
TERM=unknown
PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games
JUJU_HOME=/tmp/juju/stgraber-sample
LANG=en_CA.UTF-8
JUJU_ORIGIN=distro
SUDO_COMMAND=/usr/bin/python -m juju.agents.machine --logfile /tmp/juju/stgraber-sample/machine-agent.log --zookeeper-servers 10.0.3.1:40010 --juju-directory /tmp/juju/stgraber-sample --machine-id 0 --session-file /var/run/juju/stgraber-sample-machine-agent.zksession --pidfile /tmp/juju/stgraber-sample/machine-agent.pid
SHELL=/bin/bash
JUJU_ZOOKEEPER=10.0.3.1:40010
JUJU_UNIT_NS=stgraber-sample
JUJU_SERIES=precise
SUDO_USER=stgraber
JUJU_PUBLIC_KEY=ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQC6yjMe+wWsH9xgor39al4p+W22D7Io8+n0ZahNEWyTG0rLZDYMQryrXUDYJRvAbiCVfTB4e7waLTDoaK5sSqoa0GoexYCIgFduOBHZfjWHu9HcpIeoq5Bc+XmOYQaoFjL4YEc2GAP//8CEmGLCqC/+rO36YbBPjd0176pAJQ7R2Bym+4k2/VvA4Plw439IdElGMgK2ge+5xc0qq7iph+ITCriR1eYCorA6T2j97ufddvQO/fmOh9+HoQ4Y+i6mKSPNyO9m87+KImwF1XX/ocQRBO9eYkqWM992ZqXG4H62r+NoRNwW4R9c5nF6rUc8x1StTpp3L0A0ybIYjRuV3m+J stgraber@lantea
JUJU_MACHINE_ID=0
PWD=/home/stgraber
PYTHONPATH=/usr/bin:/usr/lib/python2.7:/usr/lib/python2.7/plat-i386-linux-gnu:/usr/lib/python2.7/lib-tk:/usr/lib/python2.7/lib-old:/usr/lib/python2.7/lib-dynload:/usr/local/lib/python2.7/dist-packages:/usr/lib/python2.7/dist-packages:/usr/lib/python2.7/dist-packages/PILcompat:/usr/lib/python2.7/dist-packages/gst-0.10:/usr/lib/python2.7/dist-packages/gtk-2.0:/usr/lib/pymodules/python2.7:/usr/lib/python2.7/dist-packages/ubuntu-sso-client:/usr/lib/python2.7/dist-packages/ubuntuone-client:/usr/lib/python2.7/dist-packages/ubuntuone-control-panel:/usr/lib/python2.7/dist-packages/ubuntuone-storage-protocol

You'll notice that JuJu overrides PYTHONPATH with 2.7 paths when lxc-ls is a python3 script.
This in turn causes the python interpreter to fail as can be seen below:
stgraber@lantea:~$ export PYTHONPATH=/usr/bin:/usr/lib/python2.7:/usr/lib/python2.7/plat-i386-linux-gnu:/usr/lib/python2.7/lib-tk:/usr/lib/python2.7/lib-old:/usr/lib/python2.7/lib-dynload:/usr/local/lib/python2.7/dist-packages:/usr/lib/python2.7/dist-packages:/usr/lib/python2.7/dist-packages/PILcompat:/usr/lib/python2.7/dist-packages/gst-0.10:/usr/lib/python2.7/dist-packages/gtk-2.0:/usr/lib/pymodules/python2.7:/usr/lib/python2.7/dist-packages/ubuntu-sso-client:/usr/lib/python2.7/dist-packages/ubuntuone-client:/usr/lib/python2.7/dist-packages/ubuntuone-control-panel:/usr/lib/python2.7/dist-packages/ubuntuone-storage-protocol
stgraber@lantea:~$ python3
Fatal Python error: Py_Initialize: Unable to get the locale encoding
  File "/usr/lib/python2.7/encodings/__init__.py", line 123
    raise CodecRegistryError,\
                            ^
SyntaxError: invalid syntax
Aborted (core dumped)
stgraber@lantea:~$

So the bug is actually in juju which doesn't pass a clean environment to the scripts it's calling and triggers this bug.