Add Port forwarding logging inside sshd

[Julien T <julien.t43@gmail.com>]

Hello Debian ssh maintainers,

I did not find this in current wishlist and I think it's worth it from a security point of view

https://blog.rootshell.be/2009/03/01/keep-an-eye-on-ssh-forwarding/
https://bugzilla.redhat.com/show_bug.cgi?id=1323810

Asking original author if an updated patch is available

Thanks

Jul