message: fix encryption bug real bug is in paddle_serving_client __init__ with open
diff: @@ -198,12 +198,12 @@ class Client(object):
  self.rpc_timeout_ms = rpc_timeout
  def use_key(self, key_filename):
  - with open(key_filename, "r") as f:
  + with open(key_filename, "rb") as f:
  self.key = f.read()
  def get_serving_port(self, endpoints):
  if self.key is not None:
  - req = json.dumps({"key": base64.b64encode(self.key)})
  + req = json.dumps({"key": base64.b64encode(self.key).decode()})
  else:
  req = json.dumps({})
  r = requests.post("http://" + endpoints[0], req)
  