Upgrade Helm version to 2.16 for CiaB and sample comac configs

Also removed unnecessary override values from COMAC sample.

Change-Id: Id7683f68cca61564ef7f8d5c3cee6f436db9a10e
diff --git a/comac/kubespray/extra-vars.yaml b/comac/kubespray/extra-vars.yaml
index 034ca39..e05a6d2 100644
--- a/comac/kubespray/extra-vars.yaml
+++ b/comac/kubespray/extra-vars.yaml
@@ -53,4 +53,4 @@
 
 helm_enabled: true
 helm_deployment_type: host
-helm_version: v2.15.0
+helm_version: v2.16.1