remove coding: from cython files, utf-8 is default encoding

src/borg/chunker.pyx

@@ -1,5 +1,3 @@
-# -*- coding: utf-8 -*-
-
 API_VERSION = '1.2_01'
 
 import errno

src/borg/hashindex.pyx

@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 from collections import namedtuple
 
 cimport cython