Add encryption to persistent files for the ubuntu livecd.

diff -ru initrd.d/scripts/casper-helpers initrd-persist.d/scripts/casper-helpers
--- initrd.d/scripts/casper-helpers	2017-02-10 22:33:56.362269774 -0600
+++ initrd-persist.d/scripts/casper-helpers	2017-02-10 22:34:17.293539058 -0600
@@ -191,6 +191,25 @@
     fi
 }
 
+setup_crypt() {
+    modprobe ${MP_QUIET} -b "dm-crypt"
+    # Most of the following stolen from local-top/cryptroot
+    cryptcreate="/sbin/cryptsetup luksOpen $1 $2"
+    cryptkey="Unlocking the disk $1 ($2)\nEnter passphrase: "
+    if [ -x /bin/plymouth ] && plymouth --ping; then
+	cryptkeyscript="plymouth ask-for-password --prompt"
+	cryptkey=$(printf "$cryptkey")
+    else
+	cryptkeyscript="/lib/cryptsetup/askpass"
+    fi
+
+    $cryptkeyscript "$cryptkey" | $cryptcreate --key-file=- &&
+    /sbin/udevadm settle
+    if [ -e "/dev/mapper/$2" ]; then
+	echo "/dev/mapper/$2"
+    fi
+}
+
 find_cow_device() {
     pers_label="${1}"
     cow_backing="/${pers_label}-backing"
@@ -221,6 +240,12 @@
                 try_mount "${devname}" "${cow_backing}" "rw" || continue
                 cow_backing_mp=$(where_is_mounted "${devname}")
                 if [ -e "${cow_backing_mp}/${pers_fpath}" ]; then
+                    # check to see if its a luks devices, this is probably better than get_fstype
+                    if cryptsetup isLuks "${cow_backing_mp}/${pers_fpath}"; then
+			echo $(setup_crypt "${cow_backing_mp}/${pers_fpath}" ${pers_label})
+			return 0
+                    fi
+                    
                     echo $(setup_loop "${cow_backing_mp}/${pers_fpath}" "loop" "/sys/block/loop*")
                     return 0
                 else