Settings: persist double tap to wake state

After disabling double tap to wake and rebooting, the state would be
persisted in the device, but it would display incorrect checkbox state.

Fixes JIRA bug BACON-92

Change-Id: Ie99e59872778dcdc3028e1770d97507fd831f515
Signed-off-by: Roman Birg <roman@cyngn.com>
Merge remote-tracking branch 'carbon/kk' into kitkat