Upload disabled for admin ?

Where admin user (uid == 1) is uploading a file using the "attach" button (Javascript callback), the upload looks like everything is fine but when submiting the form, nothing is saved.

Problem comes from upload.module, at line 331, where we have :
if ($user->uid != 1) {
// Here something.php.pps becomes something.php_.pps
$file->filename = upload_munge_filename($file->filename, NULL, 0);
$file->description = $file->filename;
}

Solution is just to remove the test in order to allow admin user to apply attachments. I thought this can be a security issue but using classical method (browsing, adding the file and just submitting the form) is correctly working for admin user.