[TwigBundle] fixed XSS in the exception template

Author: fabpot

src/Symfony/Bundle/TwigBundle/Resources/views/Exception/exception.html.twig

@@ -12,7 +12,7 @@
                 </div>
 
                 <h1>
-                    {{ exception.message|replace({"\n": '<br />'})|format_file_from_text }}
+                    {{ exception.message|e|replace({"\n": '<br />'})|format_file_from_text }}
                 </h1>
 
                 <div>