Use remote URI, not display URI, to match repositories

Summary:
I derped this up, and it passed my tests because the two URIs are the same for hosted repositories.

Match repositories against their remote URI (like `https://github.com/user/repo.git`), not their display URI (like `/diffusion/X/`).

Test Plan: i r dums

Reviewers: talshiri, btrahan

Reviewed By: talshiri

CC: aran

Differential Revision: https://secure.phabricator.com/D8082