When we save the VM disks, we now use compression to prepare
the base disk so that it reduces the base disk file sizes to
a much smaller base. For the infra hosts this reduces the file
from ~23GB to ~8GB. Once this is done, we then also create a
copy-on-write image in the original disk's place so that the
VM can be booted up to verify functionality or continue work
without having to re-run the 'deploy-vms' playbook.
Change-Id: If95b71d8625b4d5b2a036cec13952e4fd73cecd4
c72cc198c4