Add flavor create and delete API calls for openstack-nova

1. Harden Flavor
2. Update FlavorApi and FlavorAsyncApi by adding create(...) and
delete(...) methods
3. Add flavor_new.json and ParseCreateFlavorTest
4. Add create and delete tests into FlavorApiExpectTest

Change-Id: I3ea15883fb655d9a1dc48fb4ed1b1613d4975d93
Merge pull request #1065 from i11/master

Add flavor create and delete API calls for openstack-nova