Datasources values not being saved correctly during traffic updates

[danpat]

The SegmentDataContainer class is not storing the datasource IDs for segments correctly:

osrm-backend/include/extractor/segment_data_container.hpp

Lines 119 to 133 in 0affec8

	auto GetForwardDatasources(const DirectionalGeometryID id)
	{
	const auto begin = datasources.begin() + index[id] + 1;
	const auto end = datasources.begin() + index[id + 1];
	return boost::make_iterator_range(begin, end);
	}
	auto GetReverseDatasources(const DirectionalGeometryID id)
	{
	const auto begin = datasources.begin() + index[id];
	const auto end = datasources.begin() + index[id + 1] - 1;
	return boost::adaptors::reverse(boost::make_iterator_range(begin, end));
	}

The logic here sort of looks like it assumes that the datasource is the same in both directions - the code looks like it may have just been ported forward from the first revision of this code, without ever splitting the forward/reverse logic.

This bug has no practical effect on routing, but the debug tiles and annotations=sources results contain bad data.

[danpat]

Fixed by #4352