Zabbix Server and Zabbix Proxy processes are crushes when do ODBC check of item with missing macros value.

Steps to reproduce:

1. Create an Database Monitor item to PostgreSQL
2. Use a key like this 'db.odbc.select[some_name,,"Driver=PostgreSQL;Server=server;Port=\{$PG.PORT};Database=postgres"]'
3. Do not define {$PG.PORT} anywhere
4. Proxy or server will crush trying to execute this check