Upgrading libcontainer to v0.1.1

Due to the crazy vendoring process, I made a mistake by pushing the
libcontainer specific changes into docker directly. Hence I reverted
that change using ca64798526fd110950405b26132acc07baf5968f.

This commit fixes the revert by updating the libcontainer to v0.1.1
which carries the fix that is reverted.

Signed-off-by: Madhu Venugopal <madhu@socketplane.io>