Create /openstack/log base directory
Create /openstack/log base directory

Each container makes use of a subdirectory underneath the host's
/openstack/log directory as a mount point for /var/log. Ensure that this
base directory is created upfront on each LXC host to avoid a potential
race condition when containers recursively create their subdirectories.

Change-Id: I0be2139b6dc266a27bc14d68e60232d0e40844b1

os-cloud/openstack-ansible-lxc_hosts,os-cloud/openstack-ansible-lxc_hosts,openstack/openstack-ansible-lxc_hosts,openstack/openstack-ansible-lxc_hosts