Use legacy docker repository for kubernetes

Change-Id: I163160b437908b7af3bf6226ff4580bafbd7c47a
diff --git a/kubernetes/pool/cluster.yml b/kubernetes/pool/cluster.yml
index 0f961a3..252a0b7 100644
--- a/kubernetes/pool/cluster.yml
+++ b/kubernetes/pool/cluster.yml
@@ -1,6 +1,7 @@
 classes:
 - service.kubernetes.pool.cluster
 - service.docker.host
+- system.linux.system.repo.docker_legacy
 parameters:
   _param:
     # component docker images