update helm to v2.7.0 (#1875)

* update helm to v2.7.0

* Update main.yml

roles/download/defaults/main.yml

@@ -117,10 +117,12 @@ kibana_version: "v4.6.1"
 kibana_image_repo: "gcr.io/google_containers/kibana"
 kibana_image_tag: "{{ kibana_version }}"
 
-helm_version: "v2.2.2"
+# Intentionally missing 'v' prefix. See https://github.com/lachie83/k8s-helm/issues/20
+helm_version: "2.7.0"
 helm_image_repo: "lachlanevenson/k8s-helm"
 helm_image_tag: "{{ helm_version }}"
-tiller_version: "{{ helm_version }}"
+# Fix when helm_version is fixed
+tiller_version: "v2.7.0"
 tiller_image_repo: "gcr.io/kubernetes-helm/tiller"
 tiller_image_tag: "{{ tiller_version }}"