NavigationBarSettings: fix delay when toggling force navigationbar

 * Our implementation differs from cm's, so we need to disable another
   preference instead of the hardware keys disable preference

Change-Id: I9172bebdfc26fab912a407980822a8ed38e727ad
Buttons: disable waking with volume keys by default

Change-Id: I26d0778702f6e861903adee834754a731677b874