NULL first element in RecursiveRegexIterator

``` php
$leaf) {
var_dump($key, $leaf);
break;
}
```

Different results for HHVM and PHP
HHVM:

```
HipHop VM 3.5.1 (rel)
Compiler: tags/HHVM-3.5.1-0-gb723e67c88bc008676687a04dff00db1faf250b3
Repo schema: a395edf8708632a3d09f417dbd9b1bd1d5b50bbe
```

```
NULL
NULL
```

PHP:

```
PHP 5.4.21 (cli) (built: Oct 16 2013 21:09:16)
Copyright (c) 1997-2013 The PHP Group
Zend Engine v2.4.0, Copyright (c) 1998-2012 Zend Technologies
```

```
int(0)
array(1) {
[0]=>
int(1)
}
```