git ignore custom mods/themes; fix check duplicate kill

I run script
<code>$php cron_zkb.php</code>
and get error:
Database error: Duplicate entry '34873218' for key 'kll_external_id'
SQL: UPDATE kb3_kills JOIN kb3_mails ON kb3_mails.kll_id = kb3_kills.kll_id SET kb3_kills.kll_external_id = 34873218, kb3_mails.kll_external_id = 34873218, kll_modified_time = UTC_TIMESTAMP() WHERE kb3_kills.kll_id = 32730 AND kb3_kills.kll_external_id IS NULL
PHP Fatal error:  SQL error (Duplicate entry '34873218' for key 'kll_external_id' in /home/u5577/domains/insp.su/killboard/common/includes/class.dbnormalquery.php on line 46

This patch fix problem.