Not all ways of loading manifests skip over chart files

[squaremo]

From @stefanprodan in #993:

I discovered that not all files inside the templates dir are ignored. For example a PodDisruptionBudget gets applied even if it's part of a chart.

apiVersion: policy/v1beta1
kind: PodDisruptionBudget
metadata:
  name: {{ template "memcached.fullname" . }}
spec:
  selector:
    matchLabels:
      app: {{ template "memcached.fullname" . }}
      chart: "{{ .Chart.Name }}-{{ .Chart.Version }}"
      release: "{{ .Release.Name }}"
      heritage: "{{ .Release.Service }}"
  minAvailable: {{ .Values.pdbMinAvailable }}

With the above file, Flux will run into this error:

ts=2018-05-07T08:44:46.764045009Z caller=loop.go:89 component=sync-loop err="loading resources from repo: parsing file at "/tmp/flux-working640881799/repo/charts/memcached/templates/pdb.yaml": parsing YAML doc from "charts/memcached/templates/pdb.yaml": yaml: unmarshal errors:\n line 4: cannot unmarshal !!map into string"

A chart example can be found here: https://github.com/stefanprodan/weave-flux-helm-demo/tree/master/charts/memcached