Fixes issue #1864. Given the simple set-up:
a --> b --> c
^-----------|
This would translate into an edge based graph (ab) -> (bc),
(bc) -> (ca), (ca) -> (ab).
Starting at the end of the one-way street (ab) and going to
the beginning, the query has to find a self-loop within the
graph (ab) -> (bc) -> (ca) -> (ab), as both nodes map to the
same segment (ab).