Fix the wrong error message

    """Check that there's at least 'amount' space that can be made

    available on /cache."""

    self.script.append(('apply_patch_space(%d) || abort("Not enough free space '

                        'on /system to apply patches.");') % (amount,))

                        'on /cache to apply patches.");') % (amount,))

  def Mount(self, mount_point, mount_options_by_format=""):

    """Mount the partition with the given mount_point.