add 'hawkular/metrics' when updating config

roles/openshift_metrics/tasks/update_master_config.yaml

@@ -3,7 +3,7 @@
   modify_yaml:
     dest: "{{ openshift.common.config_base }}/master/master-config.yaml"
     yaml_key: assetConfig.metricsPublicURL
-    yaml_value: "https://{{ openshift_metrics_hawkular_hostname}}"
+    yaml_value: "https://{{ openshift_metrics_hawkular_hostname}}/hawkular/metrics"
   notify: restart master
   tags:
     - update_master_config