swclock: select a default reference file
swclock: select a default reference file

If $RC_SVCDIR/shutdowntime does not exist, we need a default reference
file. It is safe to use @PREFIX@/sbin/runscript for this purpose.

Reported-By: Robin H. Johnson <aa3b04a87f185a8b919ce94fe21b810489ffb8d4@gentoo.org>
X-Gentoo-Bug: 376249
X-Gentoo-Bug-URL: http://bugs.gentoo.org/show_bug.cgi?id=376249

OpenRC/openrc,OpenRC/openrc,dwfreed/openrc,williamh/openrc,williamh/openrc,dwfreed/openrc,OpenRC/openrc,williamh/openrc,dwfreed/openrc