ci.mariadb.org to use Content-type: text/plain (rfc5147) for log files

$ wget -S https://ci.mariadb.org/16646/logs/s390x-ubuntu-2004/mysqld.2.err.15

--2021-07-08 11:25:58--  https://ci.mariadb.org/16646/logs/s390x-ubuntu-2004/mysqld.2.err.15

Resolving ci.mariadb.org (ci.mariadb.org)... 95.216.219.179

Connecting to ci.mariadb.org (ci.mariadb.org)|95.216.219.179|:443... connected.

HTTP request sent, awaiting response... 

  HTTP/1.1 200 OK

  Server: nginx

  Date: Thu, 08 Jul 2021 01:26:00 GMT

  Content-Type: application/octet-stream

  Content-Length: 411783

  Last-Modified: Wed, 07 Jul 2021 19:30:51 GMT

  Connection: keep-alive

  ETag: "60e600eb-64887"

  Strict-Transport-Security: max-age=31536000; includeSubdomains;

  X-Frame-Options: SAMEORIGIN

  X-XSS-Protection: 1;mode=block

  Accept-Ranges: bytes

Length: 411783 (402K) [application/octet-stream]

Saving to: ‘mysqld.2.err.15’