Flavors are being moved to the API database for CellsV2. Add a task to
perform online data migrations as required for both the initial
migration of flavors to the Nova API database in a new Newton deployment
and for all required migrations when upgrading from Mitaka.
Also include the creation and use of a new flavor in this role's
functional testing.
Change-Id: I6b562476a6db8fdbaba81f5872734e5efdb522e1