Adding extra rc commands to fix incidentd with respect to selinux

Incidentd has sepolicy rules to allow it to write to
/data/misc/incidents/ but it needs the directory to already be created.
This modification will set the service to be UID/GID system and create
the directory under system permissions.

Test: no selinux denials related to incidentd on bootup
Bug: 64275854
Change-Id: I0f4db90f4eeb6dae5019e5bc1df590bd781a9507