Fixed dumpep argument.

src/TwigExtension.php

@@ -350,10 +350,10 @@ class TwigExtension extends \Twig_Extension {
   /**
    * Dumps information about variables.
    */
-  public function drupalDump() {
+  public function drupalDump($var) {
     $var_dumper = '\Symfony\Component\VarDumper\VarDumper';
     if (class_exists($var_dumper)) {
-      call_user_func($var_dumper . '::dump', func_get_args());
+      call_user_func($var_dumper . '::dump', $var);
     }
     else {
       trigger_error('Could not dump the variable because symfony/var-dumper component is not installed.', E_USER_WARNING);