streamline dropbear setup

config/etc/dropbear-initramfs/config

@@ -0,0 +1 @@
+DROPBEAR_OPTIONS="-p 222"

post-debootstrap-installer.sh

@@ -22,7 +22,7 @@ apt-get -y install locales
 
 ### boot
 
-apt-get -y install mdadm cryptsetup systemd systemd-sysv dropbear btrfs-tools firmware-linux
+apt-get -y install mdadm cryptsetup systemd systemd-sysv dropbear-initramfs btrfs-tools firmware-linux
 
 # generate minimal mdadm.conf
 mdadm --examine --scan | perl -pe 's/.*\/dev\/md\/?([0-9]+) .*UUID\=(.+?) .*/ARRAY \/dev\/md$1 UUID=$2/' > /etc/mdadm/mdadm.conf
@@ -30,9 +30,6 @@ mdadm --examine --scan | perl -pe 's/.*\/dev\/md\/?([0-9]+) .*UUID\=(.+?) .*/ARR
 # concat user keys for cryptsetup unlocking at boot
 cat /hardware-setup/authorized_keys/* > /etc/dropbear-initramfs/authorized_keys
 
-# set dropbear port to something other than 22, because of openssh
-sed -i 's/DROPBEAR_PORT=.*/DROPBEAR_PORT=222/' /etc/default/dropbear
-
 # after cryptsetup, mdadm, ... because of update-initramfs
 apt-get -y install linux-image-amd64