Bug 1947: Failure when closing with no tab

https://winscp.net/tracker/1947

Source commit: 6ed517749343ced569ce6c9aaec4fedd4f26e0aa

source/forms/CustomScpExplorer.cpp

@@ -5029,7 +5029,7 @@ void __fastcall TCustomScpExplorerForm::FormCloseQuery(TObject * /*Sender*/,
       }
     }
 
-    if (CanClose)
+    if (CanClose && HasActiveTerminal())
     {
       CanClose = CanCloseQueue();
     }