As there is a function named attach_interface to pass
a interface to container now, we do not need to relay on
python impolementation for lxc-device any more.

changelog: 10/15/2014: serge: fail immediately if run as non-root.
changelog: 10/15/2014: serge: add explicit error message on bad usage (fix build failure)
Signed-off-by: Dongsheng Yang <yangds.fnst@cn.fujitsu.com>
Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com>