sap_ha_pacemaker_cluster: fix stonith resource dup

During the previous change of the stonith code a conditional
was removed that did not apply to the GCP default, but is
required for other platform default stonith resources that
use host maps.

Author: ja9fuchs

roles/sap_ha_pacemaker_cluster/tasks/construct_vars_stonith.yml

@@ -109,6 +109,9 @@
       loop_control:
         loop_var: stonith_host_item
         label: "{{ stonith_host_item }}"
+      when:
+        - (hostvars[stonith_host_item].__sap_ha_pacemaker_cluster_stonith_default).id
+          not in (__sap_ha_pacemaker_cluster_stonith_resource | d([])| map(attribute='id'))
 
     # The location constraints are needed, when the fence resource is configured
     # per host and must not run on the host it targets.