Fix backward compatibility with single network engine definitions.

Change-Id: Ib022b5b3bfdac630312c97b06ca100b0ef4a1673
diff --git a/tests/pillar/master_cluster.sls b/tests/pillar/master_cluster.sls
index 06dcace..68a0e51 100644
--- a/tests/pillar/master_cluster.sls
+++ b/tests/pillar/master_cluster.sls
@@ -68,9 +68,8 @@
       address: 10.0.175.100
       allow_privileged: true
     network:
-      cnis:
-      - calico
       calico:
+        enabled: true
         calicoctl_image: calico/ctl
         cni_image: calico/cni
         etcd: