[AUDIT] Add End of Event record

This patch adds an end of event record type. It will be sent by the kernel as
the last record when a multi-record event is triggered. This will aid realtime
analysis programs since they will now reliably know they have the last record
to complete an event. The audit daemon filters this and will not write it to
disk.

Signed-off-by: Steve Grubb <sgrubb redhat com>
Signed-off-by: Eric Paris <eparis@redhat.com>