Comment 10 for bug 1298611

Stéphane, all that is needed is to add the following to abstractions/lxc/container-base and abstractions/lxc/start-container:
  signal,
  ptrace,

Obviously, confinement could be more interesting, but like with dbus we should err on the side of caution and just let these through. Adding this rules gives us equivalent confinement to lxc on 13.10.