fix sharding connect failed when enable_proxy_scramble=true

src/obproxy/proxy/mysqllib/ob_proxy_session_info_handler.cpp

@@ -220,11 +220,8 @@ int ObProxySessionInfoHandler::rewrite_login_req_by_sharding(ObClientSessionInfo
       LOG_WARN("fail to encrypt_passwd_to_stage1", K(ret));
     } else {
       passwd_string += 1;
-      OMPKHandshake handshake;
       int64_t actual_len = 0;
-      char scramble_buf[SCRAMBLE_LENGTH + 1] = {0};
-      handshake.get_scramble(scramble_buf, SCRAMBLE_LENGTH + 1, actual_len);
-      ObString scramble_string(actual_len, scramble_buf);
+      const ObString &scramble_string = client_info.get_scramble_string();
       if (OB_FAIL(ObClientUtils::get_auth_password_from_stage1(passwd_string,
               scramble_string, pwd_buf, pwd_buf_len, actual_len))) {
             LOG_WARN("fail to get get_auth_password_from_stage1", K(ret));