Explicitly call "/etc/rc.d/vmd stop". This issues graceful shutdown commands

to running VMs (at least for OpenBSD ones), but the stop routine for system
daemons is not usually called at shutdown.
Earlier version with just "vmd stop" ok reyk@ kn@, ajacoutot@ reminded me
to hide the contextless "vmd(ok)" text which looks bad, I did so and wrapped
it with a "stopping VMs" message (it can take some time, especially when you
have multiple VMs, so better to have some clear feedback).

src/etc/rc

@@ -1,4 +1,4 @@
-#	$OpenBSD: rc,v 1.526 2018/07/11 08:31:48 florian Exp $
+#	$OpenBSD: rc,v 1.527 2018/07/11 21:49:37 sthen Exp $
 
 # System startup script run by init on autoboot or after single-user.
 # Output and error are redirected to console by init, and the console is the
@@ -337,6 +337,12 @@ if [[ $1 == shutdown ]]; then
 			echo '.'
 		fi
 
+		if /etc/rc.d/vmd check > /dev/null; then
+			echo -n 'stopping VMs'
+			/etc/rc.d/vmd stop > /dev/null
+			echo '.'
+		fi
+
 		[[ -f /etc/rc.shutdown ]] && sh /etc/rc.shutdown
 	fi