Prunner start fails with defect `data.json`

[Sebobo]

Prunner cannot start when the data.json is defect and shows the following error.

> prunner/prunner --path Packages --data Data/Persistent/prunner
  INFO[0001] Loaded 3 pipeline definitions pipelines=do_content_release: Packages/Application/XYZ.XYZ/pipelines.yml, do_content_publishing: Packages/Application/XYZ.XYZ/pipelines.yml, do_content_rollout: Packages/Application/XYZ.XYZ/pipelines.yml
 FATAL[0001] Error: loading from store: loading data: decoding JSON: EOF
Script prunner/prunner --path Packages --data Data/Persistent/prunner handling the prunner event returned with error code 1

I assume this happened during a shutdown of prunner that didn't finish properly.
Question is: what to do?
We could rename the broken file and start with a new one IMO but not prevent startup.

[hlubek]

We had a possible synchronization issue in shutdown, maybe it was caused by that.

I'm a bit hesitant to just ignore broken state by default, but we could add a flag to ignore it and rename it to a backup for inspection / not losing data (and log an error of course).