Fix exception being thrown if CMHW is not installed.
Happens during debugging when mmp'ing the app.

Change-Id: Ief84a812696ef3f2515701790f96649cbde0f7d9

@alviteri: Adapted to crDroid
Add missing isKeyDisablerSupported() method and fix the build after this commit: https://github.com/crdroidandroid/android_packages_apps_Settings/commit/ebf9120b74bc22a40c002a1bfd01379451c09b42