CachingIterator: fixed IteratorAggregate -> Iterator conversion

Author: dg

src/Latte/Runtime/CachingIterator.php

@@ -41,7 +41,7 @@ public function __construct($iterator)
 		} elseif ($iterator instanceof \IteratorAggregate) {
 			do {
 				$iterator = $iterator->getIterator();
-			} while ($iterator instanceof \IteratorAggregate);
+			} while (!$iterator instanceof \Iterator);
 
 		} elseif ($iterator instanceof \Traversable) {
 			if (!$iterator instanceof \Iterator) {