Fix race condition in flavor tests

* Flavor tests (admin) create and delete flavors globally, This causes race
  condition for Flavor list tests where the list test is using the
  currently created flavors for further operations

Use locally created flavor reference in Flavor list tests

Change-Id: Id557a58008cf42e94524b061acaad9bb89f42ec7
Closes-Bug: #1267949
Merge "Fix race condition in flavor tests"