Sensor: Make getId() more varied

Apps from different developers will now receive a different
ID for the same dynamic sensor.  Additionally, all apps
will now receive a different/new ID for the same dynamic
sensor after a factory reset.

Bug: 28775590, 29547335
Change-Id: I15b48b974cbb1d53cc33dfdb7b9eb5f1b562190c
2 files changed