Add k8s-ha-calico-flannel-virtlet model.

Change-Id: I75c463d202600547464738dca43aa90a8afaa326
diff --git a/classes/cluster/k8s-ha-calico-flannel-virtlet/.env b/classes/cluster/k8s-ha-calico-flannel-virtlet/.env
new file mode 100644
index 0000000..407e2d1
--- /dev/null
+++ b/classes/cluster/k8s-ha-calico-flannel-virtlet/.env
@@ -0,0 +1 @@
+EXTRA_FORMULAS="ntp"