#91 cubrid_list_dbs() requires connection_id while in mysql_list_dbs() connection_id is optional

[Jira Trac]

In [mysql_list_dbs()|http://www.php.net/manual/en/function.mysql-list-dbs.php] connection resource is optional but [cubrid_list_dbs()|http://www.php.net/manual/en/function.cubrid-list-dbs.php] requires it. Would be great to have same behavior as in MySQL for compatibility.