A couple of setup.py fixes (apache#5338)

* setup: fix long description read in python2

* setup: fix git_get_sha in python3

Fix apache#5317

setup.py

@@ -4,6 +4,7 @@
 from __future__ import print_function
 from __future__ import unicode_literals
 
+import io
 import json
 import os
 import subprocess
@@ -16,14 +17,14 @@
 with open(PACKAGE_FILE) as package_file:
     version_string = json.load(package_file)['version']
 
-with open('README.md', encoding='utf-8') as f:
+with io.open('README.md', encoding='utf-8') as f:
     long_description = f.read()
 
 
 def get_git_sha():
     try:
-        s = str(subprocess.check_output(['git', 'rev-parse', 'HEAD']))
-        return s.strip()
+        s = subprocess.check_output(['git', 'rev-parse', 'HEAD'])
+        return s.decode().strip()
     except Exception:
         return ''