Unmount /root/config in case of error.

When there is an error, the Exit() handler unmounts filesystems within
the chroot. This adds /root/config to the list used when /proc/mounts is
not available.

functions/exit.sh

@@ -29,7 +29,7 @@ Exit ()
 			umount ${DIRECTORY} > /dev/null 2>&1 || true
 		done
 	else
-		for DIRECTORY in /dev/shm /dev/pts /dev /proc /selinux /sys
+		for DIRECTORY in /dev/shm /dev/pts /dev /proc /selinux /sys /root/config
 		do
 			umount -f chroot/${DIRECTORY} > /dev/null 2>&1 || true
 		done