CORD-3207 Make ONOS and Kafka service names configurable

Change-Id: I022dfce94a1d8b25662bbcc3610a4a4175804c85
diff --git a/xos-services/volt/templates/_helpers.tpl b/xos-services/volt/templates/_helpers.tpl
index a19e6f7..c18ccb4 100644
--- a/xos-services/volt/templates/_helpers.tpl
+++ b/xos-services/volt/templates/_helpers.tpl
@@ -53,7 +53,7 @@
   password: {{ .Values.xosAdminPassword | quote }}
   endpoint: xos-core:50051
 event_bus:
-  endpoint: cord-kafka
+  endpoint: {{ .Values.kafkaService | quote }}
   kind: kafka
 logging:
   version: 1