Fix infinite loop in routespl when fdp uses compound edges.
Fix infinite loop in routespl when fdp uses compound edges.

ellson/graphviz,ellson/graphviz,ellson/graphviz,ellson/graphviz,ellson/graphviz,ellson/graphviz,ellson/graphviz,ellson/graphviz,ellson/graphviz,ellson/graphviz,ellson/graphviz