Whoever conveys real property by a deed or mortgage which contains a covenant that it is free from all encumbrances shall, if it appears by a public record that an actual or apparent encumbrance, known or unknown to him, exists thereon, be liable in an action of contract to the grantee, his heirs, executors, administrators, successors or assigns, for all damages sustained in removing the same.
Mass. Gen. Laws ch. 184, § 22