fix crash when selecting a random scenario in mp create

previously the game would crash (manditory child missing) in depcheck.cpp if the id of the generated scenario is not the same as the id of the outer scenario.

src/game_initialization/create_engine.cpp

@@ -337,6 +337,8 @@ void create_engine::init_generated_level_data()
 
 			const std::string& description = cur_lev->data()["description"];
 			data["description"] = description;
+			// TODO: should we also carryover [story] from the outer scenario as we do in saved_game.cpp
+			data["id"] = cur_lev->data()["id"];
 
 			cur_lev->set_data(data);
 		}