python3: use force_text on subprocess output (#40570)

setup.py

@@ -36,7 +36,7 @@ def get_version():
                              stderr=subprocess.PIPE)
         result = p.communicate()[0]
         if p.returncode == 0:
-            result = result.split()[0][1:]
+            result = result.decode('ascii').split()[0][1:]
         else:
             result = '0.0.0-%s' % len(subprocess.check_output(
                 ['git', 'rev-list', 'HEAD']).splitlines())