Bug fix: Shift-clicking OK button on Synchronization checklist window when synchronization in the background was not possible still closed the window

(cherry picked from commit 523edaf84cd5a3f8731562501da590b99f0b4ff5)

Source commit: d83619924a3fef879a816b45a56611b0fe5a04cd

source/forms/SynchronizeChecklist.cpp

@@ -1353,6 +1353,7 @@ void __fastcall TSynchronizeChecklistDialog::OkButtonClick(TObject *)
   if (Queue && (FOnQueueSynchronize == NULL))
   {
     Beep();
+    ModalResult = mrNone;
   }
   else
   {