Currently each service requires a var to be set to enable the
configuration of ceilometer for the service.
This patch makes this setting dynamic based on whether there
are any hosts in the ceilometer_all host group.
This reduces the amount of configuration required for an
environment, making OSA simpler to use.
The 'rabbitmq_servers' group_var was previously a list of
'host:port' combinations. It is now only a set of hosts.
The new 'transport_url' configuration option for oslo_messaging
is not working with SSL enabled, so SSL transport for RabbitMQ
has been temporarily disabled.
Change-Id: Ia5ba4e26b9adcfd923a93c6ea5077cbec0c4478d
30dacdf8af