message: Show start_block exception
diff: @@ -750,8 +750,10 @@ struct controller_impl {
  try {
  auto onbtrx = std::make_shared<transaction_metadata>( get_on_block_transaction() );
  push_transaction( onbtrx, fc::time_point::maximum(), true, self.get_global_properties().configuration.min_transaction_cpu_usage );
  + } catch ( const fc::exception& e ) {
  + edump((e.to_detail_string()));
  } catch ( ... ) {
  - ilog( "on block transaction failed, but shouldn't impact block generation, system contract needs update" );
  + wlog( "on block transaction failed, but shouldn't impact block generation, system contract needs update" );
  }
  clear_expired_input_transactions();
  