Use tenant_usages_client from tempest-lib

Below files have been migrated to tempest-lib-

 * tenant_usages_client.py: I94fc27bdb30e69ac22b5418d6dca0a06f51874c6
 * tenant_usages.py: I94fc27bdb30e69ac22b5418d6dca0a06f51874c6
 * test_tenant_usages_client.py: I94fc27bdb30e69ac22b5418d6dca0a06f51874c6

Now Tempest-lib provides above as stable interface
so Tempest should start using those from lib and remove its own copy.

Change-Id: Ie5ecedde40bd5b26369e3e92f463690d35f4cf3b
4 files changed