Ensure node-red is up before attempting a sell transaction

[dan13ram]

If node-red is down after sell transaction is confirmed, then the threadInfo is not updated on node-red.
This results in the threadInfo being lost, and that particular file can never be downloaded.

Thus, we could do a health-check on the node-red service before doing the sell transaction.
Or perhaps even change the order of calls so that the threadInfo is updated first before doing the on-chain transaction.