VOL-530 - make sure to return when there is an error

Change-Id: I62a50f2f84e8c4e8f1f280848fb6561c215fb18f
diff --git a/unum/docker-compose.yml b/unum/docker-compose.yml
index c016dd1..7f0d23b 100644
--- a/unum/docker-compose.yml
+++ b/unum/docker-compose.yml
@@ -20,7 +20,7 @@
       - /var/run/docker.sock:/var/run/docker.sock
 
   controller:
-    image: cord/onos:latest
+    image: onosproject/onos:1.10.9
     depends_on:
       - cluster_manager
     networks:
diff --git a/unum/swarm.go b/unum/swarm.go
index 87480d5..e5f03e8 100644
--- a/unum/swarm.go
+++ b/unum/swarm.go
@@ -46,16 +46,19 @@
 	services, err := c.client.ServiceList(context.Background(), types.ServiceListOptions{})
 	if err != nil {
 		log.Errorf("Error while quering services : %s", err.Error())
+		return nil, err
 	}
 
 	tasks, err := c.client.TaskList(context.Background(), types.TaskListOptions{})
 	if err != nil {
 		log.Error("Error while quering tasks")
+		return nil, err
 	}
 
 	nodes, err := c.client.NodeList(context.Background(), types.NodeListOptions{})
 	if err != nil {
 		log.Error("Error while quering nodes")
+		return nil, err
 	}
 
 	for _, node := range nodes {