Update http.conf

add global request config for Nginx

Author: chendelin1982

docker/proxy/config/http.conf

@@ -1,2 +1,3 @@
 limit_req_zone $binary_remote_addr zone=w9_limit_req_zone:10m rate=30r/s;
-limit_conn_zone $binary_remote_addr zone=w9_limit_conn_zone:10m;
+limit_conn_zone $binary_remote_addr zone=w9_limit_conn_zone:10m;
+limit_req_zone global zone=w9_global_limit:10m rate=500r/s;