Longhorn: Upgrade from 1.7.3 to 1.8.1

Change-Id: Ie2076df97ee3d00cbced65ad52888d3b467725d4
diff --git a/charts/longhorn-1.7.3/templates/_helpers.tpl b/charts/longhorn-1.7.3/templates/_helpers.tpl
new file mode 100644
index 0000000..3fbc2ac
--- /dev/null
+++ b/charts/longhorn-1.7.3/templates/_helpers.tpl
@@ -0,0 +1,66 @@
+{{/* vim: set filetype=mustache: */}}
+{{/*
+Expand the name of the chart.
+*/}}
+{{- define "longhorn.name" -}}
+{{- default .Chart.Name .Values.nameOverride | trunc 63 | trimSuffix "-" -}}
+{{- end -}}
+
+{{/*
+Create a default fully qualified app name.
+We truncate at 63 chars because some Kubernetes name fields are limited to this (by the DNS naming spec).
+*/}}
+{{- define "longhorn.fullname" -}}
+{{- $name := default .Chart.Name .Values.nameOverride -}}
+{{- printf "%s-%s" .Release.Name $name | trunc 63 | trimSuffix "-" -}}
+{{- end -}}
+
+
+{{- define "longhorn.managerIP" -}}
+{{- $fullname := (include "longhorn.fullname" .) -}}
+{{- printf "http://%s-backend:9500" $fullname | trunc 63 | trimSuffix "-" -}}
+{{- end -}}
+
+
+{{- define "secret" }}
+{{- printf "{\"auths\": {\"%s\": {\"auth\": \"%s\"}}}" .Values.privateRegistry.registryUrl (printf "%s:%s" .Values.privateRegistry.registryUser .Values.privateRegistry.registryPasswd | b64enc) | b64enc }}
+{{- end }}
+
+{{- /*
+longhorn.labels generates the standard Helm labels.
+*/ -}}
+{{- define "longhorn.labels" -}}
+app.kubernetes.io/name: {{ template "longhorn.name" . }}
+helm.sh/chart: {{ .Chart.Name }}-{{ .Chart.Version | replace "+" "_" }}
+app.kubernetes.io/managed-by: {{ .Release.Service }}
+app.kubernetes.io/instance: {{ .Release.Name }}
+app.kubernetes.io/version: {{ .Chart.AppVersion }}
+{{- end -}}
+
+
+{{- define "system_default_registry" -}}
+{{- if .Values.global.cattle.systemDefaultRegistry -}}
+{{- printf "%s/" .Values.global.cattle.systemDefaultRegistry -}}
+{{- else -}}
+{{- "" -}}
+{{- end -}}
+{{- end -}}
+
+{{- define "registry_url" -}}
+{{- if .Values.privateRegistry.registryUrl -}}
+{{- printf "%s/" .Values.privateRegistry.registryUrl -}}
+{{- else -}}
+{{ include "system_default_registry" . }}
+{{- end -}}
+{{- end -}}
+
+{{- /*
+ define the longhorn release namespace
+*/ -}}
+{{- define "release_namespace" -}}
+{{- if .Values.namespaceOverride -}}
+{{- .Values.namespaceOverride -}}
+{{- else -}}
+{{- .Release.Namespace -}}
+{{- end -}}
+{{- end -}}