bug #2406 Fix tokenize call in DeprecationCollector (vdechenaux)

This PR was submitted for the 2.x branch but it was merged into the 1.x branch instead (closes #2406).

Discussion
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Fix tokenize call in DeprecationCollector

Hi,

if fixes `Argument 1 passed to Twig_Environment::tokenize() must be an instance of Twig_Source, string given`

Commits
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13ca97c Fix tokenize call in DeprecationCollector

lib/Twig/Util/DeprecationCollector.php

@@ -58,7 +58,7 @@ public function collect(Iterator $iterator)
 
         foreach ($iterator as $name => $contents) {
             try {
-                $this->twig->parse($this->twig->tokenize($contents, $name));
+                $this->twig->parse($this->twig->tokenize(new Twig_Source($contents, $name)));
             } catch (Twig_Error_Syntax $e) {
                 // ignore templates containing syntax errors
             }