juju deploy fails on ppc64el because aufs is not available

[Dave Cheney]

Local provider cannot spawn lxc containers as aufs is missing.

ubuntu@winton-02:~/src/github.com/juju/testing$ juju status
environment: local
machines:
  "0":
    agent-state: started
    agent-version: 1.17.5.1
    dns-name: localhost
    instance-id: localhost
    series: trusty
  "1":
    agent-state-info: '(error: error executing "lxc-clone": lxc_container: No such
      device - aufs: error mounting /var/lib/lxc/juju-precise-template/rootfs onto
      /usr/lib/powerpc64le-linux-gnu/lxc options br=/var/lib/lxc/ubuntu-local-machine-1/delta0=rw:/var/lib/lxc/juju-precise-template/rootfs=ro;
      clone failed)'
    instance-id: pending
    series: precise
  "2":
    agent-state-info: '(error: error executing "lxc-clone": lxc_container: No such
      device - aufs: error mounting /var/lib/lxc/juju-trusty-template/rootfs onto
      /usr/lib/powerpc64le-linux-gnu/lxc options br=/var/lib/lxc/ubuntu-local-machine-2/delta0=rw:/var/lib/lxc/juju-trusty-template/rootfs=ro;
      clone failed)'
    instance-id: pending
    series: trusty
services:
  ubuntu:
    charm: cs:precise/ubuntu-4
    exposed: false
    units:
      ubuntu/0:
        agent-state: pending
        machine: "1"
  ubuntu0:
    charm: cs:trusty/ubuntu-0
    exposed: false
    units:
      ubuntu0/0:
        agent-state: pending
        machine: "2"

[Tim Penhey (thumper)]

There is now a config setting we can use to explicitly not use aufs, but keep clone:
  lxc-clone-aufs: false
If we want to disable clone entirely
  lxc-clone: false