avoid unrelated ways in turn restrictions on splitting a way

[rrankin@…]

When a way which contains a relation is split, currently JOSM adds both the ways to the relation. If the relation is a turn restriction this is the wrong thing to do and results in many problematic relations. (multiple to or from ways)

I propose that if a way is split and has a relation with a via, then only the way[s] which includes the via be included in the relation. Of course if the way is split on the via node both ways will be there. Currently ways some distance from the via can get in the relation which can require several validation iteration to correct the relations

[stoecker]

Already fixed in r2628.