func deleteUntaggedFiles(store *storage.Storage, tx *storage.Tx, files entities.Files) error {
log.Infof(2, "purging untagged files")
fileIds := make([]entities.FileId, len(files))
for index, file := range files {
fileIds[index] = file.Id
}
return store.DeleteUntaggedFiles(tx, fileIds)
}
