[BUG] scratch-file-path option from Legacy FLASH Storage still mentioned in configuration file

[nantiferov]

Describe the bug

While I was checking configuration file example which comes with deb package, I noticed that scratch-file-path option is there and first I though that it's Flash storage configuration. But after quick check it seems related to Legacy FLASH Storage

To reproduce

Install deb package for latest v6.3.4 and check /etc/keydb/keydb.conf file

Expected behavior

I'm not sure if this functionality still exists in code and built in, but I think would be better to either remove it if code was removed or add note that it's legacy stuff and storage-provider flash should be used instead.

Additional information

Any additional information that is relevant to the problem.