[Bug 20372] New: WS2_register_async_shutdown forgets to initialize local_iosb.Information to zero?

http://bugs.winehq.org/show_bug.cgi?id=20372

Summary: WS2_register_async_shutdown forgets to initialize
                    local_iosb.Information to zero?
           Product: Wine
           Version: 1.1.31
          Platform: PC
        OS/Version: Linux
            Status: NEW
          Keywords: download, patch, source
          Severity: normal
          Priority: P2
         Component: winsock
        AssignedTo: [e-mail]
        ReportedBy: [e-mail]

TCPClientSocketTest.Connect, SSLClientSocketTest.Connect, and
TCPPingerTest.Ping
all exhibit valgrind warnings like this:

Syscall param writev(vector[...]) points to uninitialised byte(s)
   at writev (writev.c:46)
   by send_request (server.c:214)
   by wine_server_call (server.c:295)
   by NTDLL_wait_for_multiple_objects (sync.c:1122)
   by wait_suspend (exception.c:85)
   by usr1_handler (signal_i386.c:1993)
 Address 0x7ffdadfc is on thread 1's stack
 Uninitialised value was created by a client request
   at mark_block_uninitialized (heap.c:187)
   by RtlAllocateHeap (heap.c:1429)
   by WS2_register_async_shutdown (socket.c:1522)
   by WS_shutdown (socket.c:3444)
   by net::TCPClientSocketWin::Disconnect (tcp_client_socket_win.cc:345)
   by net::`anonymous namespace'::TCPClientSocketTest_Connect_Test::TestBody
(tcp_client_socket_unittest.cc:110)

There are similar errors on other tests that call WS_shutdown.
This looks oddly like the problem in bug 20336, and indeed, clearing
local_iosb.Information gets rid of the warning:

--- a/dlls/ws2_32/socket.c
+++ b/dlls/ws2_32/socket.c
@@ -1526,6 +1526,7 @@ static int WS2_register_async_shutdown( SOCKET s, int
type )
     wsa->hSocket         = SOCKET2HANDLE(s);
     wsa->type            = type;
     wsa->completion_func = NULL;
+    wsa->local_iosb.Information = 0;

SERVER_START_REQ( register_async )
     {

Is this the right place to do it, or should the system be clearing
it instead somewhere else?