Auto 559 defer sigterm on server launches (ready for review, for reals, again)

Do not shutdown until all the outstanding server launch jobs handled by the supervisor are done, else we will lose track of servers that we are polling.

Still need to move storing the done jobs in cassandra into the job itself, else while the job is done, the recording of the info may not be all be done.

Probably nothing else except maybe something executing after having acquiring a lock should be waited on.