Add graphite.o.o to the list of cacti'd servers.

Change-Id: I106dd7266cfddbb9e20941453b21b345968a142e
Reviewed-on: https://review.openstack.org/27503
Reviewed-by: James E. Blair <corvus@inaugust.com>
Approved: Jeremy Stanley <fungi@yuggoth.org>
Reviewed-by: Jeremy Stanley <fungi@yuggoth.org>
Tested-by: Jenkins