Fixed warning when file disposition isn't set.

If AppStdoutDisposition and AppStderrDisposition are both missing from
the registry, the service editing GUI would incorrectly complain that
the current configuration couldn't be represented in the interface.

gui.cpp

@@ -161,7 +161,7 @@ int nssm_gui(int resource, nssm_service_t *service) {
     if (! service->rotate_bytes_high) SetDlgItemInt(tablist[NSSM_TAB_ROTATION], IDC_ROTATE_BYTES_LOW, service->rotate_bytes_low, 0);
 
     /* Check if advanced settings are in use. */
-    if (service->stdout_disposition ^ service->stderr_disposition || service->stdout_disposition & ~CREATE_ALWAYS || service->stderr_disposition & ~CREATE_ALWAYS) popup_message(dlg, MB_OK | MB_ICONWARNING, NSSM_GUI_WARN_STDIO);
+    if (service->stdout_disposition != service->stderr_disposition || (service->stdout_disposition != NSSM_STDOUT_DISPOSITION && service->stdout_disposition != CREATE_ALWAYS) || (service->stderr_disposition != NSSM_STDERR_DISPOSITION && service->stderr_disposition != CREATE_ALWAYS)) popup_message(dlg, MB_OK | MB_ICONWARNING, NSSM_GUI_WARN_STDIO);
     if (service->rotate_bytes_high) popup_message(dlg, MB_OK | MB_ICONWARNING, NSSM_GUI_WARN_ROTATE_BYTES);
 
     /* Environment tab. */