Catch Null Media Values

[eyedol]

Now media values are NULL which throws exceptions causing the app to crash at time when syncing a report.

"media": [
    {
        "id": 2,
        "type": 1,
        "link": null,
        "thumb": null
    },
    {
        "id": 4,
        "type": 1,
        "link": "6_1_1369223134.jpg",
        "thumb": "6_1_1369223134_t.jpg",
        "thumb_url": "http://testing.ushahidi.com/media/uploads/6_1_1369223134_t.jpg",
        "link_url": "http://testing.ushahidi.com/media/uploads/6_1_1369223134.jpg"
    },
    {
        "id": 5,
        "type": 2,
        "link": "http://www.youtube.com/watch?v=_ks49ZjISMM",
        "thumb": "6_v0_1369223160_t.jpg"
    }
],