Adding ATHENS_STORAGE_TYPE as Env variable doesn't override the default disk

[salehparsa]

I've noticed that if you add ATHENS_STORAGE_TYPE as an ENV variable it will just cause having supplicated ATHENS_STORAGE_TYPE and disk always stays. For instance the only way to configure S3 as a storage is adding following to the values:

storage:
  type: s3
  s3:
    region: "MY REGION"
    bucket: "MY BUCKET"
    useDefaultConfiguration: "true"