Add new logstash nodes to cacti.

* modules/openstack_project/manifests/cacti.pp: Add new logstash worker
nodes and elasticsearch nodes to cacti.

Change-Id: I51053f8aed394530dc1742f14bcff8b3d7aacf86
Reviewed-on: https://review.openstack.org/35518
Approved: James E. Blair <corvus@inaugust.com>
Reviewed-by: James E. Blair <corvus@inaugust.com>
Tested-by: Jenkins