Don't crash if STUN error message is missing ERROR-CODE attribute.

webrtc/p2p/base/relayport.cc

 /*
  *  Copyright 2004 The WebRTC Project Authors. All rights reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 #include <algorithm>
@@ skipping 806 matching lines @@
   }
 
   // We will do a keep-alive regardless of whether this request suceeds.
   // This should have almost no impact on network usage.
   entry_->ScheduleKeepAlive();
 }
 
 void AllocateRequest::OnErrorResponse(StunMessage* response) {
   const StunErrorCodeAttribute* attr = response->GetErrorCode();
   if (!attr) {
-    LOG(INFO) << "Bad allocate response error code";
+    LOG(LS_ERROR) << "Missing allocate response error code.";
   } else {
     LOG(INFO) << "Allocate error response:"
               << " code=" << attr->code()
               << " reason='" << attr->reason() << "'";
   }
 
   if (rtc::TimeMillis() - start_time_ <= kRetryTimeout)
     entry_->ScheduleKeepAlive();
 }
 
 void AllocateRequest::OnTimeout() {
   LOG(INFO) << "Allocate request timed out";
   entry_->HandleConnectFailure(connection_->socket());
 }
 
 }  // namespace cricket