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.
Merge pull request #20 from pnorman/relation_way_nodes

Remove the relations_from_way_nodes SQL.
Merge branch 'master' into gsoc13