VOL-1474: GetChildDevice support

Changes also needed to support more child
device search criteria, including onu id.

Also ran a go fmt

Change-Id: Id253ae0ae0a5a68379c8dca5fc9511ac0deb9158
diff --git a/compose/system-test.yml b/compose/system-test.yml
index 61afff2..f44ac73 100644
--- a/compose/system-test.yml
+++ b/compose/system-test.yml
@@ -169,6 +169,8 @@
       "--name=brcm_openomci_onu",
       "--kafka_adapter=${DOCKER_HOST_IP}:9092",
       "--kafka_cluster=${DOCKER_HOST_IP}:9092",
+      "--backend=etcd",
+      "--etcd=${DOCKER_HOST_IP}:2379",
       "--core_topic=rwcore"
     ]
     networks: