refactor(squash): don't record mount points in text file

The squasn mount points are recorded in text file so later clean up
script can umount them, this is not needed, the mount points are fixed
so just detect the umount by hardcoded pattern.

modules.d/99squash/clear-squash.sh

@@ -1,6 +1,6 @@
 #!/bin/bash
-SQUASH_MNT_REC=/squash/mounts
-
-mapfile -t SQUASH_MNTS < $SQUASH_MNT_REC
-
-umount --lazy -- "${SQUASH_MNTS[@]}"
+mnt="/squash/root"
+for dir in jsquash/root/*; do
+	mnt="$mnt ${dir#$SQUASH_MNT}"
+done
+umount --lazy -- $mnt

modules.d/99squash/init-squash.sh

@@ -3,9 +3,6 @@ PATH=/bin:/sbin
 
 SQUASH_IMG=/squash/root.img
 SQUASH_MNT=/squash/root
-SQUASH_MNT_REC=/squash/mounts
-
-echo $SQUASH_MNT > $SQUASH_MNT_REC
 
 # Following mount points are neccessary for mounting a squash image
 
@@ -34,9 +31,6 @@ if [ $? != 0 ]; then
     echo "Unable to setup overlay module"
 fi
 
-# These modules are no longer needed, delete to save memory
-rm -rf /usr/lib/modules/
-
 [ ! -d "$SQUASH_MNT" ] && \
 	mkdir -m 0755 -p $SQUASH_MNT
 
@@ -59,8 +53,6 @@ for file in $SQUASH_MNT/*; do
 
 	mount -t overlay overlay -o\
 		lowerdir=$lowerdir,upperdir=$upperdir,workdir=$workdir $mntdir
-
-	echo $mntdir >> $SQUASH_MNT_REC
 done
 
 exec /init.orig