kubernetes-helm: tell Helm what version it is

Helm uses its version to determine what version of Tiller (the server
component) to install. Without this patch it thinks it is `v2.11+unreleased` and
tries to download `gcr.io/kubernetes-helm/tiller:v2.11`. After the patch it
correctly downloads `gcr.io/kubernetes-helm/tiller:v2.11.0`. Fixes #49120.