schroot-create: findmnt doesn't really work the way I'd like it to

it doesn't list all mountpoints under a directory, but only if that directory matches a current mountpoint, apparently

Signed-off-by: Mattia Rizzolo <mattia@debian.org>

bin/schroot-create.sh

@@ -56,7 +56,7 @@ cleanup() {
 	cd
 	if [ -d "$SCHROOT_TARGET" ]; then
 		local i
-		for i in $(findmnt -l -c | awk '{print $1}' | grep "^$SCHROOT_TARGET"); do
+		for i in $(mount | awk '{print $3}' | grep "^$(realpath "$SCHROOT_TARGET")"); do
 			sudo umount "$i"
 		done
 		sudo rm -rf --one-file-system "$SCHROOT_TARGET" || ( echo "Warning: $SCHROOT_TARGET could not be fully removed during cleanup." ; ls "$SCHROOT_TARGET" -la )