W32 gstdio: don't close fd handle

If a handle was obtained from a fd that we got from up the stack,
we shouldn't call CloseHandle() on it in case of an error.

This is a bug. Luckily, it happens only on the error codepath, so,
hopefully, no one had hit it yet.

glib/gstdio.c

@@ -199,7 +199,8 @@ _g_win32_stat_utf16_no_trailing_slashes (const gunichar2    *filename,
 
   if (!succeeded_so_far)
     {
-      CloseHandle (file_handle);
+      if (fd < 0)
+        CloseHandle (file_handle);
       errno = w32_error_to_errno (error_code);
       return -1;
     }