Forwarding fails silently with ssh ControlMaster

[cooijmanstim]

In my ssh config I have ControlMaster auto. This causes the ssh -L command in _forward to return immediately, which _forward interprets as the remote server having terminated. As a result, any mila serve command sets up the connections and then immediately breaks them down.

Setting -o ControlMaster=no in the ssh -L command fixes the issue for me.