rpc.lockd: Unconditionally close fds as daemon

When lockd is configured with a debug level of > 0 and foreground == 0,
the process is daemonized with a truth noclose argument to daemon().
This doesn't seem to be the desired behavior because that prevents
stdout and stderr from being closed, however, stdout and stderr aren't
used anywhere else. Furthermore, the man pages state that with a higher
debug level it will use the syslog facilities to do so.

Submitted by: Caleb St. John
Discussed with: rmacklem
MFC after: 3 days
Sponsored by: iXsystems, Inc.
Differential Revision: https://reviews.freebsd.org/D29415