Code review comment for lp:~flegu/widelands/fix_some_memory_leaks

Now we're getting a compiler error:

Building CXX object src/wui/CMakeFiles/wui_common.dir/mapdetails.cc.o

/home/travis/build/widelands/widelands/src/wui/load_or_save_game.cc: In member function ‘std::unique_ptr<const SavegameData> LoadOrSaveGame::entry_selected()’:

/home/travis/build/widelands/widelands/src/wui/load_or_save_game.cc:201:9: error: could not convert ‘result’ from ‘std::unique_ptr<SavegameData>’ to ‘std::unique_ptr<const SavegameData>’

  return result;

         ^

/home/travis/build/widelands/widelands/src/wui/load_or_save_game.cc:202:1: error: control reaches end of non-void function [-Werror=return-type]

 }

 ^