Description:
------------
I use create.php example from CVS and it works when creating new ZIP archive, but when I attempt to open existing one and add file, Zip::status sets equal to ZIP:ER_RENAME or 2 and archive is not modified (file is not added).

Reproduce code:
---------------
<?php
error_reporting(E_ALL);

$thisdir = dirname(__FILE__);
$filename = $thisdir . "/test112.zip";
$zip = new Zip();

if (!$zip->open($filename/*, ZIP::CREATE*/)) {
	exit("cannot open $filename\n");
} else {
	echo "file $filename OK\n";
}

$zip->addFromString("2.txt", "=)");
$zip->close();
echo "numfiles: " . $zip->numFiles . "\n";
echo "status:" . $zip->status . "\n";
?>

Expected result:
----------------
supposed to get:
numfiles: 1
status: 0

Actual result:
--------------
actually get:
numfiles: 1
status: 2