message: fix bugs in my changes to on_block in producer_plugin
diff: @@ -57,6 +57,7 @@ class producer_plugin_impl {
  if( bsp->header.timestamp <= _last_signed_block_time ) return;
  if( bsp->header.timestamp <= _start_time ) return;
  if( bsp->block_num <= _last_signed_block_num ) return;
  + if( _producers.find( bsp->header.producer ) != _producers.end() ) return;
  const auto& active_producer_to_signing_key = bsp->active_schedule.producers;
  @@ -71,7 +72,7 @@ class producer_plugin_impl {
  if( itr != active_producer_to_signing_key.end() ) {
  auto private_key_itr = _private_keys.find( itr->block_signing_key );
  if( private_key_itr != _private_keys.end() ) {
  - auto d = bsp->header.digest();
  + auto d = bsp->sig_digest();
  auto sig = private_key_itr->second.sign( d );
  _last_signed_block_time = bsp->header.timestamp;
  _last_signed_block_num = bsp->block_num;
  