code: function newFromIdentity(identity, region) {
    var service = identity.serviceByName('object-store', region);
    var endpoint = service.publicURL;
    var os = new ObjectStorage(identity.token(), endpoint);
  
    return os;
  }
docs: Create a new ObjectStorage instance from an IdentityServices
  Identity.
  
  @param {Identity} identity
  An identity with a service catalog.
  @param {string} region
  The availability zone. e.g. 'az-1.region-a.geo-1'. If this is
  omitted, the first available object storage will be used.
  @param {Function} fn
  A callback, which will receive an Error (if applicable) and an
  ObjectStorage instance.