QuietHours: Change Logic (1/2)

Makes sense to me that turning QuietHours
    on should TURN QUIET HOURS ON with
    default time constraints applied.

I.E. QuietHours between 12:00am && 12:00am
    means QuietHours all day.  Having to
    adjust end time to 11:59 is redundant
    and not exactly the clearest implementation.
    Especially when we have a QuickToggle that
    directly toggles the setting on/off.

Change-Id: I36e30a3be7d5a521bb85edff51f1c4134f623e67