Fix issue with loadRelativeEdges()

Summary: I'm going to just delete all this code at some point, but fixing it now means piles of single gets, so unbreak it first. I'll file something.

Test Plan: Releeph is less fataley.

Reviewers: andrewjcg, btrahan

Reviewed By: andrewjcg

CC: aran

Differential Revision: https://secure.phabricator.com/D6945