fix gevent patch_subprocess side effect on py2 decoding, fixes
@@ -907,7 +907,7 @@ class Py3:
raise exceptions.CommandError(msg, error_code=e.errno)
output, error = process.communicate()
- if self._is_python_2:
+ if self._is_python_2 and isinstance(output, str):
output = output.decode('utf-8')
error = error.decode('utf-8')
retcode = process.poll()
