nagios: try a different way to not run mail_queue check externally

Revert the previous thing that tried to move a template to a file, and
instead move it back to a template and just conditionalize it only to
apply on rdu3_internal nagios.

Signed-off-by: Kevin Fenzi <kevin@scrye.com>

roles/nagios_server/templates/nagios/services/mail_queue.cfg.j2

@@ -6,6 +6,7 @@ define service {
   use                   defaulttemplate
 }
 
+{% if nagios_location == "rdu3_internal" %}
 define service {
   host_name             bastion01.{{datacenter}}.fedoraproject.org
   service_description   mail_queue_redhat
@@ -13,3 +14,4 @@ define service {
   max_check_attempts    7
   use                   defaulttemplate
 }
+{% endif %}