Auditd initial commit

Initial commit for an audit daemon that
writes kernel audit messages to a log
file. The daemon runs in uid "audit" or
AID_AUDIT.

The log files are located at /data/misc/audit/
The daemon maintains two files at this location:
audit.log and optionally audit.old. On boot (
if the file is non-zero in size), or
when a fixed threshold is hit, the daemon rotates
audit.log to audit.old.

Optionally, if passed the -k option, the daemon polls
dmesg for all lines that contain "audit" and writes
them into the log. After that it continues to operate
as normal, receiving the messages from the netlink
socket.

Change-Id: I5b5037a5a8b39a054213848249afb7808f8b0ffa