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 thought so too at first.  Blew 3 hours that way before seeing that it is actually cleaner if the object store is the canonical place for addressing what (versioning/backing-up/etc) is appropriate when the store is used for significant operations.  This method is the way that the client explicitly tells us.  Problems like waiting-for-auto-to-detect-if-we-are-master and standby-promoting-to-master-then-failing work out much simpler this way.

Maybe the method name can be improved however.  `prepareForMasterWriteAccess` ?  And i will beef up javadoc.