开启webdav后，访问子目录，总是路径缺失/seafdav/，需修改 nginx.conf，如下：
location /seafdav/ {
proxy_pass http://127.0.0.1:8080;
proxy_set_header Host $host;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_set_header X-Forwarded-Host $server_name;
proxy_set_header X-Forwarded-Proto $scheme;
proxy_read_timeout 1200s;
client_max_body_size 0;
access_log /var/log/nginx/seafdav.access.log seafileformat;
error_log /var/log/nginx/seafdav.error.log;
}