permission error fix in test_cluster_spooler.py teardown

[barentine]

Addresses issue test passes, but in teardown the servers need a slight delay to close before releasing the temporary directory for deletion. Also works with a 0.1 s delay on my machine, but just to be safe... left it at 1 s.

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[David-Baddeley]

just did a re-merge to see if we get clean tests.