md5sum: adapt for python 3 support

tests/md5sum.py

@@ -1,44 +1,44 b''
 #!/usr/bin/env python
 #
 # Based on python's Tools/scripts/md5sum.py
 #
 # This software may be used and distributed according to the terms
 # of the PYTHON SOFTWARE FOUNDATION LICENSE VERSION 2, which is
 # GPL-compatible.
 
 from __future__ import absolute_import
 
 import os
 import sys
 
 try:
     import hashlib
     md5 = hashlib.md5
 except ImportError:
     import md5
     md5 = md5.md5
 
 try:
     import msvcrt
     msvcrt.setmode(sys.stdout.fileno(), os.O_BINARY)
     msvcrt.setmode(sys.stderr.fileno(), os.O_BINARY)
 except ImportError:
     pass
 
 for filename in sys.argv[1:]:
     try:
         fp = open(filename, 'rb')
     except IOError as msg:
         sys.stderr.write('%s: Can\'t open: %s\n' % (filename, msg))
         sys.exit(1)
 
     m = md5()
     try:
-        for data in iter(lambda: fp.read(8192), ''):
+        for data in iter(lambda: fp.read(8192), b''):
             m.update(data)
     except IOError as msg:
         sys.stderr.write('%s: I/O error: %s\n' % (filename, msg))
         sys.exit(1)
     sys.stdout.write('%s  %s\n' % (m.hexdigest(), filename))
 
 sys.exit(0)