Fix g5sensord never sleeping & adjust init layout

* Service needs use to system:misc permissions so that libsensors can
  send USR signals to sleep/resume correctly.
* Reorganize init.rc so that post-fs-data is created in correct order, to
  prevent crash of g5sensord service on fresh boot (no /data/misc/sensors)

Change-Id: Ib3b3af8729a8e1e910683de9ae03e63756da4ef6