If a commit fails, we return its error as the error of the function that called it.

If we're behing a proxy such as Caddy, the remote address will be that
of the proxy, so we have to use the X-Forwarded-For header that the
proxy injects instead.

This makes it easier to re-use the session after a while, and to
implement a logout option (by just deleting the session)

It fits the need more naturally.

The key will be cycled later.

Not that it matters much in this context, but it makes the SSH command happy