Fix parsing error when Glance V2 image contains optional locations

[baseman79]

Seeing parsing error when image from Glance V2 contains "locations"

According to Glance API V2:

A list of objects, each of which describes an image location. Each object contains a url key, whose value is a URL specifying a location, and a metadata key, whose value is a dict of key:value pairs containing information appropriate to the use of whatever external store is indicated by the URL.

Add a new Location object, and replace the locations from List to List

  "images": [{
    "container_format": "bare",
    "min_ram": 0,
    "updated_at": "2017-10-05T07:37:07Z",
    "file": "/v2/images/xxxx/file",
    "owner": "xxxx",
    "id": "xxxx",
    "size": 10000,
    "self": "/v2/images/xxxx",
    "disk_format": "qcow2",
    "direct_url": "rbd://xxxx/images/xxxx/snap",
    "hw_disk_bus": "virtio",
    "schema": "/v2/schemas/image",
    "status": "active",
    "tags": [],
    "visibility": "public",
    "locations": [{
      "url": "rbd://xxxx/images/xxxx/snap",
      "metadata": {}
    }],
    "min_disk": 0,
    "virtual_size": null,
    "name": "xxx",
    "checksum": "xxx",
    "created_at": "2017-10-05T07:37:00Z",
    "hw_vif_model": "virtio",
    "protected": false
  }],
  "schema": "/v2/schemas/images",
  "first": "/v2/images?name=aselvana-vnfd-deployment-control-function"
}

[vinodborole]

@baseman79 thanks for the fix, can you please add a test case for this?

[baseman79]

@vinodborole sure thing, will add one shortly, thx

[auhlig]

Thanks @baseman79