Bug fix: pubsub does not publish message data.
Bug fix: pubsub does not publish message data.

The official API documentation for `publish` endpoint requires `data` and `label` nested under `message` key. (see https://cloud.google.com/pubsub/v1beta1/topics/publish)

```json
{
  "topic": string,
  "message": {
    "data": bytes,
    "label": [
      {
        "key": string,
        "strValue": string,
        "numValue": long
      }
    ]
  }
}
```
nemo/gcloud-node,VikramTiwari/gcloud-node,jonparrott/gcloud-node,VikramTiwari/gcloud-node,chrishiestand/gcloud-node,stephenplusplus/gcloud-node,callmehiphop/gcloud-node,t9nf/gcloud-node,stephenplusplus/gcloud-node,jonparrott/gcloud-node,Muffasa/gcloud-node,jgeewax/gcloud-node,VikramTiwari/gcloud-node,savethefails/gcloud-node,SimpleEmotion/gcloud-node,savethefails/gcloud-node,stephenplusplus/gcloud-node-bigquery-debug,mziccard/gcloud-node,mziccard/gcloud-node,Muffasa/gcloud-node,tcrognon/google-cloud-node,anandsuresh/gcloud-node,ofrobots/google-cloud-node,googleapis/google-cloud-node,jgeewax/gcloud-node,authbox-lib/gcloud-node,ofrobots/google-cloud-node,GoogleCloudPlatform/gcloud-node,ofrobots/google-cloud-node,nemo/gcloud-node,callmehiphop/gcloud-node-ghpages,jcking/google-cloud-node,authbox-lib/gcloud-node,phw/gcloud-node,chrishiestand/gcloud-node,callmehiphop/gcloud-node-ghpages,googleapis/google-cloud-node,phw/gcloud-node,anandsuresh/gcloud-node,GoogleCloudPlatform/gcloud-node,googleapis/google-cloud-node,chrishiestand/gcloud-node,savethefails/gcloud-node,t9nf/gcloud-node,callmehiphop/gcloud-node,stephenplusplus/gcloud-node-bigquery-debug,tcrognon/google-cloud-node,jcking/google-cloud-node,pcostell/gcloud-node,Muffasa/gcloud-node,jcking/google-cloud-node,SimpleEmotion/gcloud-node,pcostell/gcloud-node,nemo/gcloud-node,t9nf/gcloud-node,jmptrader/gcloud-node,googleapis/google-cloud-node,authbox-lib/gcloud-node,blowmage/gcloud-node,SimpleEmotion/gcloud-node,GoogleCloudPlatform/gcloud-node,pcostell/gcloud-node,stephenplusplus/gcloud-node,jmptrader/gcloud-node,blowmage/gcloud-node