Summary: Last bits needed to get remotefilelog over bundle2 working. Includes tests.
Test Plan: Ran tests, including with `--extra-config-opt experimental.bundle2-exp=True`
Reviewers: davidsp, akushner, pyd, rmcelroy, daviser, durham
Reviewed By: durham
Differential Revision: https://phabricator.fb.com/D1671738
Tasks: 5568731
Signature: t1:1671738:1415676482:b9e7a1f308919526b0c41fee54d89da876518ec7
