fixed #1464 - change so persistence dir is only backed up if node is HA ...

...master or HA disabled; handles the case of HA autodetect selecting master hence the complexity.

also fixes some leaks in test and improves atomic file update support in FileBasedObjectStore.
(incorporates new logging from #1469)
i will look if we can combine `injectMgmt` and `prepareForSharedUse`.  for some reason it felt like we couldn't but i think you are right, we should be able at least to do that!