MFC r335287, r335290

r335287:
praudit(1): return 0 on success

Cherry pick https://github.com/openbsm/openbsm/commit/ed83bb3

Submitted by: aniketp
Reviewed by: rwatson, 0mp
Obtained from: OpenBSM
Sponsored by: Google, Inc. (GSoC 2018)
Pull Request: https://github.com/openbsm/openbsm/pull/32

r335290:
praudit(1): add tests

Submitted by: aniketp
X-MFC-With: 335287
Sponsored by: Google, Inc. (GSoC 2018)
Differential Revision: https://reviews.freebsd.org/D15751

Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

The last big commit: let usr.sbin/ use WARNS=6 by default.

Enable building of OpenBSM command line tools:

- audit(8) - audit subsystem management tool
- auditd(8) - audit trail and subsystem management daemon
- auditreduce(1) - audit trail reduction tool
- praudit(1) - audit trail printing tool

Could probably use a NO_AUDIT make.conf flag.

Obtained from: TrustedBSD Project