mailserver, rspamd: fix duplicate and syntactically wrong header settings (PL-132289).
webgateway/nginx, with modsecurity activated: Fix rotation of audit
log files. Log files matching the pattern /var/log/nginx/modsec_*.log
are now rotated via copying and then truncating the open log. All nginx
modsecurity logfiles need to follow the naming scheme modsec_* to not
accidentally grow unrotated. This is the naming convention suggested by our
nginx modsecurity configuration examples. A small amount of log entries
written at the time of rotation might be lost (PL-132296).