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)
Was this the same as the previous default behaviour? I thought we didn't abort, so one could look at the web console to see what had gone wrong with the apps during their startup.