Low level discovery rules can not be created in zabbix 1.9.8

It is impossible to add Discovery rule. After filling in required details and clicking save, following error message is displayed:

ERROR: Cannot add discovery rule

Incorrect arguments passed to function

It seems that variable $item_db_fields in the api/classes/class.citemgeneral.php function checkInput is declared in such a way as to prevent creating items without declared value_type.

Workaround is to add line

'value_type' => '0',

after the line 231 ('filter' => $filter,) in file host_discovery.php.