Minions are a Kubernetes concept that maps directly to Magnum's
concept of nodes. This patch renames the column 'minions_address'
to 'node_addresses', so that it is more clear what is stored there
and to be more agnostic across each Container Orchestration
Environment.
Change-Id: I551b0774a08492cb0d45c17b905a830a173522e0
Partial-Implements: blueprint multiple-bay-templates