netrom: Fix sock_orphan() use in nr_release

While debugging another bug it was found that NetRom socks
are sometimes seen unorphaned in sk_free(). This patch moves
sock_orphan() in nr_release() to the beginning (like in ax25,
or rose).

Reported-and-tested-by: Bernard Pidoux f6bvp <f6bvp@free.fr>
Signed-off-by: Jarek Poplawski <jarkao2@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>