Update pruning processing config
Update pruning processing config

Fix problem where file isn't actually written to disk after
modification (possibly because not closed?).  Ensure file is closed after
use.

artefactual/archivematica,eckardm/archivematica,michal-ruzicka/archivematica,michal-ruzicka/archivematica,michal-ruzicka/archivematica,eckardm/archivematica,artefactual/archivematica,sevein/archivematica,sevein/archivematica,artefactual/archivematica,eckardm/archivematica,michal-ruzicka/archivematica,sevein/archivematica,artefactual/archivematica,sevein/archivematica,eckardm/archivematica