VOL-595 - container image name consistency and general cleanup

Change-Id: Iccac1ccba61537cefa046118df139196e9e87713
diff --git a/compose/docker-compose-logstash-swarm.yml b/compose/docker-compose-logstash-swarm.yml
index 1f566ed..814ed9d 100644
--- a/compose/docker-compose-logstash-swarm.yml
+++ b/compose/docker-compose-logstash-swarm.yml
@@ -2,7 +2,7 @@
 
 services:
   logstash:
-    image: cord/logstash
+    image: "${REGISTRY}voltha/logstash:${TAG:-latest}"
     environment:
       - log.level=info
       - xpack.monitoring.enabled=false