This migrates the above files from tempest. This includes tempest
commits:
* flavors_client.py : Id153ba7b5ff838532fd7bf0e2b72815141c2e250
* test_flavors_client.py: Ibf160ba20e26a9c1f216a2e741bdfa9f45c4f0d0
* flavors.py : Ica929c402a3d042ae751302384e68853eb28b405
* flavors_access.py : Ica929c402a3d042ae751302384e68853eb28b405
* flavors_extra_specs.py: Ica929c402a3d042ae751302384e68853eb28b405
to see the commit history for these files refer to the above Change-Ids
in the tempest repository
Partially implements blueprint migrate-service-clients-to-tempest-lib
Change-Id: I3de529b1e0db298530e54fd2c871d40f29614126