Remove a security note about deprecated StringUtils equals

Author: pimpreneil

components/security/secure_tools.rst

@@ -5,22 +5,6 @@ The Symfony Security component comes with a collection of nice utilities
 related to security. These utilities are used by Symfony, but you should
 also use them if you want to solve the problem they address.
 
-Comparing Strings
-~~~~~~~~~~~~~~~~~
-
-The time it takes to compare two strings depends on their differences. This
-can be used by an attacker when the two strings represent a password for
-instance; it is known as a `Timing attack`_.
-
-Internally, when comparing two passwords, Symfony uses a constant-time
-algorithm; you can use the same strategy in your own code thanks to the
-:class:`Symfony\\Component\\Security\\Core\\Util\\StringUtils` class::
-
-    use Symfony\Component\Security\Core\Util\StringUtils;
-
-    // is some known string (e.g. password) equal to some user input?
-    $bool = StringUtils::equals($knownString, $userInput);
-
 Generating a Secure random Number
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~