Bug#942100: openssh-server: /etc/ssh/sshd_config unconditionally overwritten by update

>  Port 22

That should have been

  Port 2222

Additionally, when I reviewed the `permit-root-login` debconf settings against the postinst I got a bit confused.

In `create_sshdconfig` it says

        if [ "$permit_root_login" != true ]; then
                sed -i 's/^#*PermitRootLogin .*/PermitRootLogin yes/' \
                        "$new_config"
        fi
 
My debconf setting for `$permit_root_login` is `true` so the `$new_config` is left untouched and has a

  #PermitRootLogin  prohibit-password

It took me a second think to realize that `prohibit-password` still permits root logins.
However, what left me dumb-founded was that if I were to change `permit-root-login` to any value other then `true`, even `false` or `no` (debconf says it's a boolean), that that would change `$new_config` to have

  PermitRootLogin yes

FWIW, PermitRootLogin supports four values.

I find the debconf/postinst behavior *very* unintuitive, so I didn't change my debconf answers and put

  PermitRootLogin no

in a `/etc/ssh/ssdh_config.d/*.conf` snippet so it takes precedence, per `man 5 sshd_config`, no matter how the postinst changes the `$new_config`.