newsyslog: Eliminate unnecessary sleep(10) when -R and -s are specified

After going through the signal work list, during which do_sigwork()
is called and essentially does nothing because -s and -R were
specified on the command line, newsyslog will sleep for 10 seconds
as the (verbose) code says: "Pause 10 seconds to allow daemon(s)
to close log file(s)".

However, the man page verbiage for -R (and -s) seems quite clear
that this sleep() is unnecessary because the daemon was expected
to have already closed the log file before calling newsyslog.

PR: 210020
Submitted by: David A. Bright <david_a_bright@dell.com>
MFC after: 1 week
Sponsored by: Dell Inc.
Differential Revision: https://reviews.freebsd.org/D6727