vpn-manager: Fix l2tp/ipsec connections to Windows RRAS server

l2tp_manager.cc

 // Copyright (c) 2011 The Chromium OS Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "vpn-manager/l2tp_manager.h"
 
 #include "base/file_util.h"
 #include "base/logging.h"
 #include "base/string_util.h"
 #include "chromeos/process.h"
@@ skipping 60 matching lines @@
   AddBool(&l2tpd_config, "require authentication",
           FLAGS_require_authentication);
   AddString(&l2tpd_config, "name", FLAGS_user);
   AddBool(&l2tpd_config, "ppp debug", FLAGS_ppp_debug);
   AddString(&l2tpd_config, "pppoptfile", ppp_config_path);
   AddBool(&l2tpd_config, "length bit", FLAGS_length_bit);
   return l2tpd_config;
 }
 
 std::string L2tpManager::FormatPppdConfiguration() {
-  std::string pppd_config = StringPrintf(
+  std::string pppd_config(
       "ipcp-accept-local\n"
       "ipcp-accept-remote\n"
       "refuse-eap\n"
       "noccp\n"
       "noauth\n"
       "crtscts\n"
       "idle 1800\n"
       "mtu 1410\n"
       "mru 1410\n"
       "nodefaultroute\n"
@@ skipping 111 matching lines @@
   return pid == l2tpd_->pid();
 }
 
 void L2tpManager::Stop() {
   if (l2tpd_->pid()) {
     LOG(INFO) << "Shutting down L2TP";
     Terminate();
   }
   OnStopped(false);
 }