message: [db-bootstrapper] use read-only for waypoint generation
  Closes:
diff: @@ -41,7 +41,7 @@ fn main() -> Result<()> {
  let db = DbReaderWriter::new(
  LibraDB::open(
  &opt.db_dir,
  - false, /* readonly */
  + !opt.commit, /* readonly */
  None, /* pruner */
  )
  .with_context(|| format_err!("Failed to open DB."))?,
  