bugfix: for addresses, see PR

bugfix for address ids being set to 'undefined' and causing records to be lost from the index; this was evident in records having an id of `poi-address-node-undefined`

here is a record for QA named `Infront Web, Kings, United States` which should also generate a separate address record (below, named `244 5th Avenue, Kings, United States`)

tested locally, works.

```javascript
{
  "_index": "pelias",
  "_type": "osmnode",
  "_id": "42465563",
  "_version": 1,
  "found": true,
  "_source": {
    "center_point": {
      "lat": 40.6286801,
      "lon": -74.0229613
    },
    "name": {
      "default": "Infront Web"
    },
    "type": "node",
    "address": {
      "number": "244",
      "street": "5th Avenue",
      "zip": "10001",
      "city": "New York"
    },
    "admin0": "United States",
    "admin1": "New York",
    "admin2": "Kings",
    "suggest": {
      "input": [
        "infront web"
      ],
      "payload": {
        "id": "osmnode\/42465563",
        "geo": "-74.0229613,40.628680100000004"
      },
      "output": "Infront Web, Kings, United States",
      "weight": 6
    }
  }
}
```

```javascript
{
  "_index": "pelias",
  "_type": "osmnode",
  "_id": "poi-address-node-42465563",
  "_version": 1,
  "found": true,
  "_source": {
    "name": {
      "default": "244 5th Avenue"
    },
    "type": "node",
    "center_point": {
      "lat": 40.6286801,
      "lon": -74.0229613
    },
    "admin0": "United States",
    "admin1": "New York",
    "admin2": "Kings",
    "suggest": {
      "input": [
        "244 5th avenue"
      ],
      "payload": {
        "id": "osmnode\/poi-address-node-42465563",
        "geo": "-74.0229613,40.628680100000004"
      },
      "output": "244 5th Avenue, Kings, United States",
      "weight": 8
    }
  }
}
```