VOL-595 - container image name consistency and general cleanup

Change-Id: Iccac1ccba61537cefa046118df139196e9e87713
diff --git a/compose/docker-compose-zk-kafka-test.yml b/compose/docker-compose-zk-kafka-test.yml
index 09c562b..748a9c2 100644
--- a/compose/docker-compose-zk-kafka-test.yml
+++ b/compose/docker-compose-zk-kafka-test.yml
@@ -4,7 +4,7 @@
   # Single-node zookeeper service
   #
   zookeeper:
-    image: wurstmeister/zookeeper
+    image: "${REGISTRY}wurstmeister/zookeeper:${ZK_TAG:-latest}"
     ports:
     - 2181:2181
     environment:
@@ -13,7 +13,7 @@
   # Single-node kafka service
   #
   kafka:
-    image: wurstmeister/kafka
+    image: "${REGISTRY}wurstmeister/kafka:${KAFKA_TAG:-latest}"
     ports:
      - 9092:9092
     environment:
@@ -22,4 +22,4 @@
       KAFKA_AUTO_CREATE_TOPICS_ENABLE: 'true'
       SERVICE_9092_NAME: "kafka"
     volumes:
-      - /var/run/docker.sock:/var/run/docker.sock
\ No newline at end of file
+      - /var/run/docker.sock:/var/run/docker.sock