Use uint32_t to hold return values from ERR_get_error() and ERR_peek_error().

net/tools/flip_server/spdy_ssl.cc

 // Copyright (c) 2012 The Chromium 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 "net/tools/flip_server/spdy_ssl.h"
 
 #include "base/logging.h"
 #include "openssl/err.h"
 #include "openssl/ssl.h"
 
@@ skipping 85 matching lines @@
 
 SSL* CreateSSLContext(SSL_CTX* ssl_ctx) {
   SSL* ssl = SSL_new(ssl_ctx);
   SSL_set_accept_state(ssl);
   PrintSslError();
   return ssl;
 }
 
 void PrintSslError() {
   char buf[128];  // this buffer must be at least 120 chars long.
-  int error_num = ERR_get_error();
+  uint32_t error_num = ERR_get_error();
   while (error_num != 0) {
     ERR_error_string_n(error_num, buf, sizeof(buf));
     LOG(ERROR) << buf;
     error_num = ERR_get_error();
   }
 }
 
 }  // namespace net