Migrate test_aggregates_basic_ops to Tempest clients

This patch uses Tempest clients instead of Official clients. This is
part of the migrating all scenario tests to using tempest own clients.

Partially-implements: bp:tempest-client-scenarios
Change-Id: I1cdf391652fbb14d5c527e8702c392904ef35a37
Merge "Migrate test_aggregates_basic_ops to Tempest clients"