Currently os_tempest is used by multiple deployement tools
and each of them have different methods of configuring
services and currently tempest_service_available_{service_name}
are setted based on group vars and group vars is not used at
all places which leads enable user to specifically define a
list of tempest_service_available_{service_name} which is too
hectic.
By introducing tempest_services:
- aodh
- neutron
will set those vars automatically and makes it easier for
handling tempest_service_availabe vars.
Depends-On: https://review.openstack.org/#/c/649653/
Change-Id: I8734f38206b73e6547a6ec545f07f625e844ed66
Signed-off-by: Chandan Kumar <chkumar@redhat.com>