Fix problem with image defaults getting overwritten

{{- define "esgf.component.image" -}}

{{- $context := index . 0 -}}

{{- $overrides := index . 1 -}}

{{- $image := mergeOverwrite $context.Values.image $overrides -}}

{{- $image := deepCopy $context.Values.image | merge $overrides -}}

image: {{ printf "%s/%s:%s" $image.prefix $image.repository $image.tag }}

imagePullPolicy: {{ $image.pullPolicy }}

{{- end -}}