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)
yes, i've changed that aspect of default behaviour.  called this out in #1469 and meant to do so here.

we don't have an absolute requirement but i have become increasingly irritated with trying to manage processes that fail but stay running, & i think the default behaviour should be that if instructions specified on the CLI fail, the command should exit with a nonzero result code.  for any other behaviour you specify a CLI argument.

do you feel strongly that the previous behaviour was better?