JCLOUDS-458: Addressing suggestions in PR-31

minor changes


This is sample json given in https://developers.google.com/storage/docs/cross-origin
[
    {
      "origin": ["http://example.appspot.com"],
      "responseHeader": ["x-meta-goog-custom"],
      "method": ["GET", "HEAD", "DELETE"],
      "maxAgeSeconds": 3600
    }
]
In xml api there is "methods" and "origins" but not in json api
https://developers.google.com/storage/docs/reference-methods#elements-for-cors