message: work around lack of cached protocol version in chainspec loader
diff: @@ -354,8 +354,8 @@ impl ChainspecLoader {
  };
  let highest_block_era_id = highest_block.header().era_id();
  - let cached_protocol_version = maybe_cached_protocol_version
  - .expect("cached protocol version must exist if we have a stored block");
  + let cached_protocol_version =
  + maybe_cached_protocol_version.unwrap_or_else(|| Version::new(1, 0, 0));
  let current_chainspec_activation_point =
  self.chainspec.protocol_config.activation_point.era_id;
  