server_tag off 在http2协议模式下不生效

[solosky]

Ⅰ. Issue Description

我这边有个需求是需要隐藏掉Server: Tengine/2.3.3，根据文档做如下配置后测试：

    server {
        listen       443 ssl http2;
        server_name  localhost;

        ssl_certificate      www.shangri-la.com.cert;
        ssl_certificate_key  www.shangri-la.com.key;

        ssl_session_cache    shared:SSL:1m;
        ssl_session_timeout  5m;

        ssl_ciphers  HIGH:!aNULL:!MD5;
        ssl_prefer_server_ciphers  on;

       server_tag off;
       server_tokens off;
       server_info off;

        location / {
            root   html;
            index  index.html index.htm;
        }
    }

}

Ⅱ. Describe what happened

http1.1/http1.0模式下生效，服务器没有返回Server header.

 solosky curl https://192.168.56.101/ -k -I --http1.1
HTTP/1.1 200 OK
Date: Mon, 15 Nov 2021 05:39:23 GMT
Content-Type: text/html
Content-Length: 555
Last-Modified: Mon, 15 Nov 2021 05:14:28 GMT
Connection: keep-alive
ETag: "6191ecb4-22b"
Accept-Ranges: bytes

➜  solosky curl https://192.168.56.101/ -k -I --http1.0
HTTP/1.1 200 OK
Date: Mon, 15 Nov 2021 05:40:41 GMT
Content-Type: text/html
Content-Length: 555
Last-Modified: Mon, 15 Nov 2021 05:14:28 GMT
Connection: close
ETag: "6191ecb4-22b"
Accept-Ranges: bytes

http 2.0 模式下不生效，服务器返回了Server header.

➜  solosky curl https://192.168.56.101/ -k -I --http2
HTTP/2 200
server: Tengine
date: Mon, 15 Nov 2021 05:39:27 GMT
content-type: text/html
content-length: 555
last-modified: Mon, 15 Nov 2021 05:14:28 GMT
etag: "6191ecb4-22b"
accept-ranges: bytes

Ⅲ. Describe what you expected to happen

http 2.0 模式期望不返回Server Header。

Ⅳ. How to reproduce it (as minimally and precisely as possible)

Ⅴ. Anything else we need to know?

1. If applicable, add nginx debug log doc.

Ⅵ. Environment:

• Tengine version (use sbin/nginx -V):

[root@vm1 nginx]# sbin/nginx -V
Tengine version: Tengine/2.3.3
nginx version: nginx/1.18.0
built by gcc 4.8.5 20150623 (Red Hat 4.8.5-44) (GCC)
built with OpenSSL 1.0.2k-fips  26 Jan 2017
TLS SNI support enabled
configure arguments: --with-http_v2_module

• OS (e.g. from /etc/os-release): CentOS Linux release 7.9.2009 (Core)
• Kernel (e.g. uname -a):
• Others: