Below is the file 'debian/dropbear.postinst' from this revision. You can also download the file.
#!/bin/sh
set -e
test "$1" = 'configure' || exit 0
echo "You must manually convert your OpenSSH host keys if required."
if test ! -s /etc/default/cokedropbear; then
cat >>/etc/default/cokedropbear <<EOT
# the TCP port that Dropbear listens on
DROPBEAR_PORT=376
# any additional arguments for Dropbear
DROPBEAR_EXTRA_ARGS=
# specify an optional banner file containing a message to be
# sent to clients before they connect, such as "/etc/issue.net"
DROPBEAR_BANNER=""
# RSA hostkey file (default: /etc/dropbear/dropbear_rsa_host_key)
#DROPBEAR_RSAKEY="/etc/dropbear/dropbear_rsa_host_key"
# DSS hostkey file (default: /etc/dropbear/dropbear_dss_host_key)
#DROPBEAR_DSSKEY="/etc/dropbear/dropbear_dss_host_key"
EOT
fi
if test -x /etc/init.d/cokedropbear; then
update-rc.d cokedropbear defaults >/dev/null
if test -x /usr/sbin/invoke-rc.d; then
invoke-rc.d cokedropbear start
else
/etc/init.d/cokedropbear start
fi
fi