No attachment of real estate shall continue in force as a lien for a longer period than fifteen years after the date thereof unless within said period the action in which such attachment was made has been prosecuted to effect and a judgment lien filed according to law. All attachments of real estate which have expired as a lien by the provisions of this section shall be deemed dissolved and the real estate shall be free from any lien or encumbrance by reason of the same and the town clerk of the town in which such real estate is situated shall, upon the request of any person interested, discharge such attachment lien by recording a discharge of lien in the land records.