Get all the states the name was in at a particular block height.
        Does NOT work on expired names.
        Return {'status': true, 'record': ...}

def rpc_get_name_at( self, name, block_height, **con_info ):
        """
        Get all the states the name was in at a particular block height.
        Does NOT work on expired names.
        Return {'status': true, 'record': ...}
        """
        if not check_name(name):
            return {'error': 'invalid name', 'http_status': 400}

        if not check_block(block_height):
            return self.success_response({'record': None})

        db = get_db_state(self.working_dir)
        names_at = db.get_name_at( name, block_height, include_expired=False )
        db.close()
        
        ret = []
        for name_rec in names_at:
            if 'opcode' not in name_rec:
                name_rec['opcode'] = op_get_opcode_name(name_rec['op'])
            
            ret.append(self.sanitize_rec(name_rec))

        return self.success_response( {'records': ret} )