port test_availability_zone into nova v3 part2

this ports test_availability_zone into nova v3 and
corresponding availability_zone_client

Partially implements blueprint nova-v3-api-tests

Change-Id: I5f38e54e3f29adeab67c60e8e3fe6db9e989a2d3
Merge "port test_availability_zone into nova v3 part2"