uhttpd: set max_requests to 12

This limits the number of concurrent users to 2 or 3 (approx. 4 connections per
user), greatly reducing DoS potential.

package/gluon-status-page/files/lib/gluon/upgrade/500-status-page

@@ -9,5 +9,7 @@ uci batch <<-EOF
 
 	set uhttpd.main.home=/lib/gluon/status-page/www
 
+	set uhttpd.main.max_requests=12
+
 	commit uhttpd
 EOF