tasks: Ensure machinectl quota value is reasonable
tasks: Ensure machinectl quota value is reasonable

It appears that when setting a limit which is greater than the size
of the underlying filesystem, machinectl does not change the quota at
all. As such, lets calculate the limit based on the /var/lib/machines
mountpoint or any of its parents.

Change-Id: I8ddc9931cbca5db8c1a411fd2581b34763179d01

openstack/openstack-ansible-lxc_hosts,openstack/openstack-ansible-lxc_hosts