Fix for removing the dirs while creating a TAR archive

The bug caused issues during the export of analytics data from advanced
reporting. The scandir has parameter were the sort can be placed, but
using UNSORTED gives you unwanted lists of files/dirs. Therefor deleting
the first 2 via array_shift, is not a proper way of dealing with this

Signed-off-by: Harold Claus <[email protected]>

Author: haroldclaus

lib/internal/Magento/Framework/Archive/Tar.php

@@ -259,10 +259,7 @@ protected function _createTar($skipRoot = false, $finalize = false)
                 );
             }
 
-            array_shift($dirFiles);
-            /* remove  './'*/
-            array_shift($dirFiles);
-            /* remove  '../'*/
+            $dirFiles = array_diff($dirFiles, ['..', '.']);
 
             foreach ($dirFiles as $item) {
                 $this->_setCurrentFile($file . $item)->_createTar();