Fix default image tag for enterprise

We're just going to hardcode this for now until we can verify that a tag
like v3.6 will always exist in the future

roles/openshift_logging/vars/openshift-enterprise.yml

@@ -1,3 +1,3 @@
 ---
 __openshift_logging_image_prefix: "{{ openshift_hosted_logging_deployer_prefix | default('registry.access.redhat.com/openshift3/') }}"
-__openshift_logging_image_version: "{{ openshift_hosted_logging_deployer_version | default(openshift_release | default ('3.5.0') ) }}"
+__openshift_logging_image_version: "{{ openshift_hosted_logging_deployer_version | default ('3.6.0') }}"

roles/openshift_metrics/vars/openshift-enterprise.yml

@@ -1,3 +1,3 @@
 ---
 __openshift_metrics_image_prefix: "{{ openshift_hosted_metrics_deployer_prefix | default('registry.access.redhat.com/openshift3/') }}"
-__openshift_metrics_image_version: "{{ openshift_hosted_metrics_deployer_version | default(openshift_release | default ('3.5.0') ) }}"
+__openshift_metrics_image_version: "{{ openshift_hosted_metrics_deployer_version | default ('3.6.0') }}"