Depends on D20420. Ref T13277. We currently spend substantial effort trying to detect and correct the URL of the "origin" remote in Git repositories.
I believe this is unnecessary, and we can always git fetch <url> ... to get the desired result instead of git muck-with-origin + git fetch origin .... We already do this in the more recent parts of the codebase (e.g., intracluster sync) and it works correctly in every case I'm aware of.