tenderloin: fix reboot process

* rebootcmd is pretty useless really, and selinux hates everything
  about it

* catch the sys.shutdown.requested from framework and kick off
  the moboot_control.sh directly

Change-Id: I74d20f8872d8ef0d8456006f3d9f5b5690ff25e6
sepolicy: additional rules

* mpdecision, sensors, moboot_control
* don't hate me for running moboot_control in the vold domain

Change-Id: Ibe6130fe3524081e45e67a2042eedff25425237b