message: fix chain active producer schedule reference
diff: @@ -497,7 +497,7 @@ signed_block chain_controller::_generate_block( block_timestamp_type when,
  _pending_block->new_producers = latest_producer_schedule;
  }
  - _pending_block->schedule_version = _head_producer_schedule().version;
  + _pending_block->schedule_version = get_global_properties().active_producers.version;
  if( !(skip & skip_producer_signature) )
  _pending_block->sign( block_signing_key );
  @@ -909,7 +909,7 @@ const producer_object& chain_controller::validate_block_header(uint32_t skip, co
  ("block producer",next_block.producer)("scheduled producer",producer.owner));
  }
  - EOS_ASSERT( next_block.schedule_version == _head_producer_schedule().version, block_validate_exception, "wrong producer schedule version specified" );
  + EOS_ASSERT( next_block.schedule_version == get_global_properties().active_producers.version, block_validate_exception, "wrong producer schedule version specified" );
  return producer;
  }
  