Remove nefarious "one_file_system" flag that silently empties archives

data/borgmatic.d/config.yaml

@@ -3,7 +3,6 @@ source_directories:
 repositories:
   - path: ssh://${STORAGE_BOX_USER}@${STORAGE_BOX_USER}.your-storagebox.de:23/./borg-repo
 
-one_file_system: true
 remote_path: borg-1.4
 ssh_command: ssh -i ~/.ssh/${SSH_KEY_NAME}