This migrates the above files from tempest. This includes tempest commits:
* aggregates_client.py : Iac7e2e59b0a5b498fb5be5c7696ebe7bb15be8fe
* test_aggregates_client.py: I3ad6761651cec5e66012d08e6b63322f53286a5c
* aggregates.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: Ia20fd3914aa6e5ac829bfd3fb88bb4f654958b53