sockets: remove use of QemuOpts from socket_listen

sockets: remove use of QemuOpts from socket_listen

The socket_listen method accepts a QAPI SocketAddress object
which it then turns into QemuOpts before calling the
inet_listen_opts/unix_listen_opts helper methods. By
converting the latter to use QAPI SocketAddress directly,
the QemuOpts conversion step can be eliminated

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-id: 1452518225-11751-3-git-send-email-berrange@redhat.com
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>