Description:
------------
DOMXPath->query() seems to totally ignore context nodes. I get 
an empty DOMNodeList when I execute a query with a context 
node.

P.S.: Your bug submission process is a real PITA. Could we 
have just one CAPTCHA, please?


Reproduce code:
---------------
// I just deleted the real code, but here's a sample
// Assume the document and xpath parser have already been
// instantiated.
/*
$doc = 
<kvps>
  <string>
    <key>My Key</key>
    <value>My Value</value>
  <string>
</kvps>
*/
$nodes = $xpath->query( '//string');

foreach ( $nodes as $node) {
  print_r( $node);
  $key = $xpath->query( '//key', $node);
  echo $key->nodeValue . "\n";
  print_r( $key);
}



Expected result:
----------------
I expect $key to be the DOMElement tagged as "key" inside of 
the current "string" element.

Actual result:
--------------
An empty NodeList