nginx auth proxy apache multiple sites

map $remote_user $proxy_client_domain {
        default $remote_user;
}

upstream newsline.linearcollider.org {
        server 127.0.1.1:80;
}

upstream linearcollider.org {
        server 127.0.2.1:80;
}

server {
    include listen_spdy_ssl.conf;
    ssl_certificate     /etc/letsencrypt/live/clarkmania.com-0001/fullchain.pem;
    ssl_certificate_key /etc/letsencrypt/live/clarkmania.com-0001/privkey.pem;

    server_name clientsites.btolab.com;

    #auth_digest_user_file /etc/nginx/passwd.client.digest;
    #auth_digest_shm_size 4m;

    root /home/h0tw1r3/sites/com.btolab/default;

    if ($not_allowed_method) {
        return 405;
    }
    
    location / {
        auth_basic 'Client Host';
        auth_basic_user_file htpasswd.clientsites;

        subs_filter_types application/javascript application/json text/*;
        subs_filter $proxy_client_domain clientsites.btolab.com;
        subs_filter http:([\\\]?/[\\\]?/)clientsites.btolab.com https:$1clientsites.btolab.com ir;

        client_max_body_size 50m;
        proxy_http_version 1.1;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header X-Forwarded-Server $http_host;
        proxy_set_header X-Forwarded-Proto $scheme;
        proxy_set_header X-HTTP-Authorization $http_authorization;
        proxy_pass http://$proxy_client_domain;
        proxy_set_header Host $proxy_client_domain;
        proxy_redirect http://$proxy_client_domain/ /;
        proxy_redirect https://$proxy_client_domain/ /;
        proxy_redirect / /;
        proxy_cookie_domain ~.* clientsites.btolab.com;
    }
}