v4: don't change an icon while switching clock/calendar

An icon (on the right) is changed while switching clock/calendar. But a calendar is always shown first after `hide()/show()` and  'time' icon can confuse an user. Demo: http://jsfiddle.net/d7ssrr9q/5/

Switched state was restored in version 3, but not in version 4 now. So I just commented toggling an icon for now.