Fix a dual inheritance

Change-Id: I09269ee16df4a889c13335e0c5af14015449d4cf
diff --git a/classes/cluster/drivetrain-ha/cicd/worker.yml b/classes/cluster/drivetrain-ha/cicd/worker.yml
index 9dc8d0c..ad824f8 100644
--- a/classes/cluster/drivetrain-ha/cicd/worker.yml
+++ b/classes/cluster/drivetrain-ha/cicd/worker.yml
@@ -1,6 +1,5 @@
 classes:
-- system.linux.system.single
-- system.jenkins.slave.docker
-- system.aptly.client.publisher
-- cluster.drivetrain-ha
-
+  - system.linux.system.single
+  - system.jenkins.slave.docker
+  - system.aptly.client.publisher
+  - cluster.drivetrain-ha