XD-2170: NoNodeException for job creation

When an admin process is elected leader/supervisor, it will query the state of all streams and jobs. It does this by iterating all streams under `/xd/deployments/streams/[stream-name]` and jobs under `/xd/deployments/jobs/[job-name]`. Under each path, it is expecting a modules node which contains all of the modules deployed for the stream or job.

The issue is that if *no* modules were deployed for the stream/job, that node will not exist because it is created lazily by the container. This is unlikely in the case of streams since a stream contains at least two modules, but is much more likely with jobs since they only contain one module.

The fix is to ensure that the `/xd/deployments/streams/[stream-name]/modules` path (and the same for
jobs) is created upfront by the supervisor prior to creating the module deployment requests. This will allow the supervisor to see that no modules for the stream/job have been deployed and thus take appropriate action.
Good point; now that we explicitly create this path we should let the exception propagate as this would indicate an expected state. I'll make the change and push.