ENYO-423: TimePicker: Current Time Does Not Initially Display

### Issue:
Integer Picker now fires a change event after every call to Value Changed (instead of just after calls to next() and previous(), as it was doing before). This resulted in a change event from the meridiem picker wrongly changing hours and minutes 
### Fix:
when the call to updateValue() originates from the meridiem picker, get the value of hours and minutes from this.value, instead of the hour and minute pickers.


Enyo-DCO-1.1-Signed-off-by: Krishna Rangarajan <krishna.rangarajan@lge.com>
I think we should probably guard against `this.value` being `null` here. One scenario that can occur, at least in the TimePickerSample, is that with the picker open, the "Reset Time" button is pressed, and the meridiem is subsequently changed.