CMsgBox: add missing disableTimeOutBar()

addendum to
CHintBox: move showTimeOutBar() to protected, add params to enableTimeOutBar()

src/gui/widget/msgbox.cpp

@@ -304,6 +304,7 @@ int CMsgBox::exec()
 		}
 	}
 
+	disableTimeOutBar();
 	return res;
 }