This adds support for a chroot variable which will be passed to the
start-stop-daemon --chroot switch to runscript.sh when starting a
daemon. This also needs to be saved so it can be used in locating the
pid file when stopping the daemon.
X-Gentoo-Bug: 524388
X-Gentoo-Bug-URL: https://bugs.gentoo.org/show_bug.cgi?id=524388