Query merging does not work correctly.

I have the following setup

```javascript
export const graph = graphql('/graphql', {
method: 'POST',
asJSON: true,
debug: true,
});

graph.fragment({
video: `on Video {
id
description
duration
videoType
}`,
category: `on Category {
id
name
categoryType
}`,
});

export const videos = graph.query('{ videos { ...video } }');

export const categories = graph.query('{ categories { ...category } }');
```

I try to use the "merge" functionality like so.
```javascript
queries.videos.merge('test');
queries.categories.merge('test');
queries.graph.commit('test').then((r) => console.log('all', r));
```

Now the query sent to my server is as follows.
```
query {
merge993382_videos :{ videos { ... video } }
merge278951_categories :{ categories { ... category } }
}

fragment video on Video {
id
description
duration
videoType
}

fragment category on Category {
id
name
categoryType
}
```

Which is, of course, invalid as the extra {} shouldn't be there around the query pieces.

I'm using graphql.js version 0.6.7