Added support for old charts

[jc36]

Without this, I lost my old charts. Maybe this will be useful to someone else.
For example, such labels on the very common jetstack/cert-manager chart:

  labels:
    app: cert-manager
    app.kubernetes.io/instance: cert-manager
    app.kubernetes.io/managed-by: Tiller
    app.kubernetes.io/name: cert-manager
    helm.sh/chart: cert-manager-v0.10.0

[atkaper]

Thanks!