avoid crash on Qt5

lazpaint/lazpaintinstance.pas

@@ -374,6 +374,7 @@ procedure TLazPaintInstance.ReportActionProgress(AProgressPercent: integer);
 var
   delay: Integer;
 begin
+  {$IFDEF LCLqt5}exit;{$ENDIF}
   if AProgressPercent < 100 then delay := 10000 else delay := 1000;
   if Assigned(FMain) then FMain.UpdatingPopup:= true;
   try

lazpaint/lazpaintmainform.pas

@@ -2695,6 +2695,7 @@ end;
 
 procedure TFMain.TimerUpdateTimer(Sender: TObject);
 begin
+  if FLazPaintInstance = nil then exit;
   TimerUpdate.Enabled := false;
   if ToolManager.ToolSleeping and not spacePressed and
      ([ssLeft,ssRight,ssMiddle] * FLayout.MouseButtonState = []) then