Switch volume button default behavior

Bug: 8151863
Changed the default to do nothing and added a check to make sure that on
the first boot after an upgrade, it will switch "Snooze" to "Do nothing"

Change-Id: I778e3eb58f465f2c3fc5be55859874cca8ab8b62

Conflicts:

	src/com/android/deskclock/AlarmAlertFullScreen.java
	src/com/android/deskclock/AlarmInitReceiver.java