Remove the relations_from_way_nodes SQL.

This SQL added relations that were parents of any nodes that were children
of included ways, but those nodes are already included by nodes_from_way_nodes
and the relations then get included by relations_from_nodes.

I've tested this with ``make check`` and with a couple of subway stop nodes and turn restriction nodes.

This should give a reasonable increase of performance because joining against way_nodes is expensive.