minor #847 Umask documentation link changed (Rvanlaak)

This PR was submitted for the 2.8 branch but it was merged into the 2.3 branch instead (closes #847).

Discussion
----------

Umask documentation link changed

The documentation link in `app_dev.php` to the permissions chapter changed.

Commits
-------

d35ee17 Documentation link changed

Author: fabpot

web/app_dev.php

@@ -4,7 +4,8 @@
 use Symfony\Component\Debug\Debug;
 
 // If you don't want to setup permissions the proper way, just uncomment the following PHP line
-// read http://symfony.com/doc/current/book/installation.html#configuration-and-setup for more information
+// read http://symfony.com/doc/current/book/installation.html#checking-symfony-application-configuration-and-setup
+// for more information
 //umask(0000);
 
 // This check prevents access to debug front controllers that are deployed by accident to production servers.