different xml elements in arrays for generated services

[cataggar]

Need a similar fix to #1097 for xml generated services. It is not obvious that this spec matches that structure:

    "BlobHierarchyListSegment": {
      "xml": {
        "name": "Blobs"
      },
      "type": "object",
      "required": [
        "BlobItems"
      ],
      "properties": {
        "BlobPrefixes": {
          "type": "array",
          "items": {
            "$ref": "#/definitions/BlobPrefix"
          }
        },
        "BlobItems": {
          "type": "array",
          "items": {
            "$ref": "#/definitions/BlobItemInternal"
          }
        }
      }
    },