Fix memory cgroup configuration for lxc-docker on Ubuntu 14.04
Step 1: enable hierarchical memory management
/etc/init. The upstart job will ensure
that the memory cgroup is configured with hierarchical stats tracking
before systemd-logind and/or docker start creating cgroups.
(Yes, it's mostly a crude hack with an obscure way of syncing with cgroup-lite. That can't be helped, though)