Error when I delete two or more files at the same folder

[IsaacAnselmo]

When I need to delete two or more files at the same folder , I got error when trying to delete the folder.

RecursiveDirectoryIterator::__construct(\app\webroot\files\cfdi\7,\pagos\app\webroot\files\cfdi\7): Acceso denegado. (code: 5)

After tracing inside UploadBehavior I found the error is caused by the array in foldersToRemove, because contain all the id to delete and the PlugIn try to delete a folder doesn'n exist.

`

    public function deleteFolder(Model $model, $path) {
    if (!isset($this->__foldersToRemove[$model->alias])) {
        return false;
    }

    $this->__foldersToRemove[$model->alias]=array_unique($this->__foldersToRemove[$model->alias]);      

    $folders = $this->__foldersToRemove[$model->alias];
    foreach ($folders as $folder) {
        if (strlen((string)$folder) === 0) {
            continue;
        }

        $dir = $path . $folder;
        $it = new RecursiveDirectoryIterator($dir);
        $files = new RecursiveIteratorIterator($it, RecursiveIteratorIterator::CHILD_FIRST);
        foreach ($files as $file) {
            if ($file->getFilename() === '.' || $file->getFilename() === '..') {
                continue;
            }

            if ($file->isDir()) {
                $this->rmdir($file->getRealPath());
            } else {
                $this->unlink($file->getRealPath());
            }
        }
        $this->rmdir($dir);
    }

    unset($this->__foldersToRemove[$model->alias]);

    return true;
}

`

[IsaacAnselmo]

I put this issue in the pull requestr #551