DB creation scripts are not included in v 3.x packages for Centos/RHEL 7, doesn't match situation described in docs: https://www.zabbix.com/documentation/3.0/manual/appendix/install/db_scripts

There are create.sql scripts in single files, but not separate ones:
/usr/share/doc/zabbix-server-pgsql-3.0.1/create.sql.gz
/usr/share/doc/zabbix-server-mysql-3.0.1/create.sql.gz