message: Remove 'rocksdb' from new context aftion file replayer, set 'inmem' as the default backend.
diff: @@ -63,9 +63,9 @@ impl Args {
  .takes_value(true)
  .value_name("STRING")
  .required(true)
  - .default_value("rocksdb")
  + .default_value("inmem")
  .possible_values(&SupportedContextKeyValueStore::possible_values())
  - .help("Choose the merkle storege backend - supported backends: 'rocksdb', 'sled', 'inmem', 'btree'"));
  + .help("Choose the merkle storege backend - supported backends: 'sled', 'inmem', 'btree'"));
  let matches = app.get_matches();
  