Distribute the queue serial file after each update

Distribute the queue serial file after each update

This patch adds distribution of the queue serial file after each write
to it (but before a new job is created and written with that ID, and
before a response is returned, so we should be safe from crashes in
between).

Currently it only logs if a node cannot be contacted, it should abort if
> 50% errors are seen.

Reviewed-by: imsnah