Just an update: as of today, even Debian provides libssl1.0.0:1.0.1e-2+deb7u16 which still generates these error logs, so it looks like the only way is still to fallback to libssl1.0.0:1.0.1e-2+deb7u12. Posted at Nginx Forum: http://forum.nginx.org/read.php?2,256373,258186#msg-258186