Nodepool sometimes provides an hp cloud instance that has the majority
of space in /dev/vdb which is mounted at /mnt. This patch repurposes
that partition as an lvm VG for containers.
Also:
* creates an LV for /opt and mounts that.
* outputs some instance info that may be useful for debugging
Closes-Bug: #1407647
Change-Id: I91a6ab3994be348b17caaf9c9200d84463076d87