When any person shall purchase at a sheriff’s sale any real estate on which the judgment upon which the execution issued was not a lien at the time of the levy, and which fact was unknown to the purchaser, the court shall set aside such sale on motion, notice having been given to the debtor as in case of action, and a new execution may be issued to enforce the judgment, and, upon the order being made to set aside the sale, the sheriff or judgment creditor shall pay over to the purchaser the purchase money; said motion may also be made by any person interested in the real estate.