Remove compatibilty note for Python 2.6 and 3.0-3.6

Author: hugovk

Tools/iobench/iobench.py

@@ -1,6 +1,3 @@
-# -*- coding: utf-8 -*-
-# This file should be kept compatible with both Python 2.6 and Python >= 3.0.
-
 import itertools
 import os
 import platform