In order to cater for artifact-based installed, and
rolling upgrades, this patch implements a set of local
facts to inform the db sync and online migrations
tasks.
The 'cinder_all_software_updated' variables will be
set by the playbook on each run to ensure that the
online migrations only happen once all venvs are
homogenous. This ensures that the playbook can be
executed in a serialised fashion and the data will
not be corrupted.
Change-Id: I9aacda78f92355374af3f4ab24d2d9a9b47491ed
bca5c325eb