rename vars to avoid double negatives and ensuing confusion

roles/openshift_metrics/defaults/main.yaml

@@ -60,5 +60,5 @@ openshift_metrics_hawkular_user_write_access: False
 
 openshift_metrics_heapster_allowed_users: system:master-proxy
 
-openshift_metrics_cassandra_disable_prometheus_endpoint: False
-openshift_metrics_hawkular_disable_prometheus_endpoint: False
+openshift_metrics_cassandra_enable_prometheus_endpoint: True
+openshift_metrics_hawkular_enable_prometheus_endpoint: True

roles/openshift_metrics/templates/hawkular_cassandra_rc.j2

@@ -56,8 +56,8 @@ spec:
           value: "/cassandra_data"
         - name: JVM_OPTS
           value: "-Dcassandra.commitlog.ignorereplayerrors=true"
-        - name: DISABLE_PROMETHEUS_ENDPOINT
-          value: "{{ openshift_metrics_cassandra_disable_prometheus_endpoint }}"
+        - name: ENABLE_PROMETHEUS_ENDPOINT
+          value: "{{ openshift_metrics_cassandra_enable_prometheus_endpoint }}"
         - name: TRUSTSTORE_NODES_AUTHORITIES
           value: "/hawkular-cassandra-certs/tls.peer.truststore.crt"
         - name: TRUSTSTORE_CLIENT_AUTHORITIES

roles/openshift_metrics/templates/hawkular_metrics_rc.j2

@@ -67,8 +67,8 @@ spec:
           value: "{{ 17 | oo_random_word }}"
         - name: TRUSTSTORE_AUTHORITIES
           value: "/hawkular-metrics-certs/tls.truststore.crt"
-        - name: DISABLE_PROMETHEUS_ENDPOINT
-          value: "{{ openshift_metrics_hawkular_disable_prometheus_endpoint }}"
+        - name: ENABLE_PROMETHEUS_ENDPOINT
+          value: "{{ openshift_metrics_hawkular_enable_prometheus_endpoint }}"
         - name: OPENSHIFT_KUBE_PING_NAMESPACE
           valueFrom:
             fieldRef: