This migrates the above files from tempest. This includes tempest commits:
* availability_zone_client.py: I593d09fcae8b7973d5f4232408c91f046022fe99
* test_availability_zone_client.py: I3ad6761651cec5e66012d08e6b63322f53286a5c
* api_schema/../availability_zone.py: Ica929c402a3d042ae751302384e68853eb28b405
to see the commit history for these files refer to the above sha1s in the tempest repository
Partially implements blueprint migrate-service-clients-to-tempest-lib
Change-Id: I573ca2cf2076bd6c3e0cb9e457f1da2a64c211da