Reset isValuePreservedInRestore in Setting::reset()

Bug: 150842661
Test: 1. atest SettingsStateTest
      2. atest PreservedSettingsRestoreHostSideTest

Reset operation brings a setting to its default state. This should
include isValuePreservedInRestore which is false for a newly initialized
setting.

Change-Id: Ife317e2ac9dbaae9d3f2abe770407558e7bdd775