MFC: r287581
Add an additional check to service(8) -e incase rcvar is blank

Sponsored by: ScaleEngine Inc.

MFC: r287576
service(8) -e does not respect /etc/rc.conf.d/* entries

PR: 173454
Submitted by: giantlock@gmail.com (original patch)

MFC r267493:

Fix two issues:

- Check for rc.d directory's existence before traversing
it;
- Don't output * when rc.d directory is empty.

PR: bin/190665
Submitted by: Oleg Ginzburg <olevole olevole ru> (with changes)

MFC r267493:

Fix two issues:

- Check for rc.d directory's existence before traversing
it;
- Don't output * when rc.d directory is empty.

PR: bin/190665
Submitted by: Oleg Ginzburg <olevole olevole ru> (with changes)