Add admin_servers_client in BaseV2ComputeAdminTest

admin_servers_client is often used in testcases inherited from
BaseV2ComputeAdminTest, so this is to add admin_servers_client
in BaseV2ComputeAdminTest's setup_clients.

Change-Id: Ia34366523a1d02cec1dbd7c6a1781df89ed6ebef
6 files changed