Description:
------------
Apologies but I'm not running the SVN version as I only have hosting access to 
PHP, but I've searched through the bugs and have found nothing. Using 5.3.0, sorry 
if this has already been fixed.

When using an XPath expression "/test/@attr1" to select one attribute, 
attributes() returns NULL when it should return the single attribute

Test script:
---------------
<?php

$xml = simplexml_load_string("<test attr1=\"a\" attr2=\"b\"></test>");

$result = $xml->xpath("/test");

var_dump ($result[0]); //Prints attributes, all fine
var_dump ($result[0]->attributes()); //Works fine

$result = $xml->xpath("/test/@attr1");

var_dump ($result[0]); //Prints attribute "attr1", all fine
var_dump ($result[0]->attributes()); //Should print same as above but returns null

?>

Expected result:
----------------
The last var_dump should have printed the same as the previous var_dump

Actual result:
--------------
The last var_dump printed null