switch to new mount system, use more safety mount options
MoKee port

Change-Id: I83cd609f1b8b0bafdd8f13255d947828e9ac1b58
build change

Change-Id: Id47489d6f3e52fb8794bb5572a79c69e9bdb27f4
enable dexopt for MoKee release

Change-Id: I826fb04b0aabb05a66b051820496cc7714c48b0b