R1:e786c44b6ffe

Relax the same-origin check in the Git commit discovery daemon

Summary:
Git accepts either "git@x:/path" or "ssh://git@x.com/path" URIs to mean the
exact same thing, which is causing some false positives and confusion,
particularly because we sometimes mutate URIs.

Since this is just a sanity check, we don't really care about the username,
domain or credentials -- matching the paths is good enough. We're just trying to
make it hard to shoot yourself in the foot by copy-pasting the same local path
into…