add basic lxc-test-ubuntu (v3)

Some features of lxc - networking and LSM configuration for instance -
are generally configured by the distro packages.  This program
tests the Ubuntu configuration.

changelog v2:
  Switch to lxc-info -i to detect ip address as stgraber suggested
  Don't look for 'expect' as I'm not using it yet.
changelog v3:
  Make sure to only read one ip address from container.

Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>
Acked-by: Stéphane Graber <stgraber@ubuntu.com>