[AUDIT] collect uid, loginuid, and comm in OBJ_PID records

Add uid, loginuid, and comm collection to OBJ_PID records.  This just
gives users a little more information about the task that received a
signal.  pid is rather meaningless after the fact, and even though comm
isn't great we can't collect exe reasonably on this code path for
performance reasons.

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