Adding a test to cover: "Show the status of a service" API

1) New test case: "test_admin_show_service_status"
   Show service status and make sure that all expected
   fields present in response
2) Re-factoring: moving negative test scenario to the
   dedicated class.

Change-Id: I09cde6142e2d76f6d5bc08202837d9de76687036
2 files changed