Description:
------------
When using the ZipArchive::renameIndex function to rename the files in a zip archive the zip becomes corrupt. I have tried several different zip files and they all become corrupt.

Reproduce code:
---------------
$client='TEST';
$zip = new ZipArchive();
if ($zip->open($targetpath,ZIPARCHIVE::OVERWRITE)===true)
{  
    // prefix all of the files with the clients name
    for($i = 0; $i < $zip->numFiles; $i++)
    {  
        $zip->renameIndex($i,$client.$zip->getNameIndex($i));
    } 
    if (!$zip->close()) echo 'Failed to rename zip';
}else echo'Failed to open zip';


Expected result:
----------------
This should open an existing zip archieve from the path $targetpath and prefix all of the filenames of its files with the word 'TEST'.

Actual result:
--------------
The files do appear to get renamed when I open the finished archieve however I am unable to extract the files from the zip because they are corrupt.