win: Fix some warnings reported by /analyze

handler/handler_main.cc

 // Copyright 2014 The Crashpad Authors. All rights reserved.
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
 //
 //     http://www.apache.org/licenses/LICENSE-2.0
 //
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,
@@ skipping 321 matching lines @@
     sigemptyset(&sa.sa_mask);
     sa.sa_flags = SA_SIGINFO;
     sa.sa_sigaction = HandleSIGTERM;
     int rv = sigaction(SIGTERM, &sa, &old_sa);
     PCHECK(rv == 0) << "sigaction";
     reset_sigterm.reset(&old_sa);
   }
 #elif defined(OS_WIN)
   ExceptionHandlerServer exception_handler_server(!options.pipe_name.empty());
 
-  std::string pipe_name;
   if (!options.pipe_name.empty()) {
     exception_handler_server.SetPipeName(base::UTF8ToUTF16(options.pipe_name));
   } else if (options.handshake_handle != INVALID_HANDLE_VALUE) {
     std::wstring pipe_name = exception_handler_server.CreatePipe();
 
     uint32_t pipe_name_length = static_cast<uint32_t>(pipe_name.size());
     if (!LoggingWriteFile(options.handshake_handle,
                           &pipe_name_length,
                           sizeof(pipe_name_length))) {
       return EXIT_FAILURE;
@@ skipping 20 matching lines @@
       database.get(), &upload_thread, &options.annotations);
 
   exception_handler_server.Run(&exception_handler);
 
   upload_thread.Stop();
 
   return EXIT_SUCCESS;
 }
 
 }  // namespace crashpad