Description:
------------
If the namespace of the insertBefore()'d element equals that of its parent, it loses the xmlns attribute, so becomes unnamespaced:( !

Reproduce code:
---------------
<?php
$main= DOMDocument::loadXML('<?xml version="1.0"?><f2f:no-xmlns xmlns:f2f="http://friend2friend.net"/>');
$new= $main->createElement('new');
$new->setAttribute('xmlns', 'http://friend2friend.net');
echo 'Main document= '.$main->saveXML().chr(13);
echo 'New element= '.$main->saveXML($new).chr(13).chr(13);
$main->firstChild->insertBefore($new, $main->firstChild->firstChild);
echo 'insertBefore() changes <new> into an unnamespaced node iff its NS matched the parent node :-( '.$main->saveXML();
?>


Expected result:
----------------
Shouldn't lose the namespace. i.e.

<f2f:no-xmlns xmlns:f2f="http://friend2friend.net"><f2f:new/></f2f:no-xmlns>


Actual result:
--------------
Loses the NS:

<f2f:no-xmlns xmlns:f2f="http://friend2friend.net"><new/></f2f:no-xmlns>