Set 'php_keepalive' 200 (#5058)

frameworks/PHP/php/deploy/nginx_php.conf

@@ -38,7 +38,7 @@ http {
         root /;
         index  index.html;
 
-        php_keepalive 100;
+        php_keepalive 200;
 
         location = /hello {
             add_header Content-Type text/plain;