init/FreeBSD: set correct PATH for xl devd

FreeBSD init scripts don't have /usr/local/{bin/sbin} in it's PATH, which
prevents `xl devd` from working properly since hotplug scripts require the set
of xenstore cli tools to be in PATH.

While there also fix the usage of --pidfile, which according to the xl help
doesn't use "=", and add braces around XLDEVD_PIDFILE.

Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
(cherry picked from commit 1d52073334)

tools/hotplug/FreeBSD/rc.d/xendriverdomain.in

@@ -29,7 +29,7 @@ xendriverdomain_startcmd()
 {
 	printf "Starting xenservices: xl devd."
 
-	${sbindir}/xl devd --pidfile=$XLDEVD_PIDFILE ${XLDEVD_ARGS}
+	PATH="${bindir}:${sbindir}:$PATH" ${sbindir}/xl devd --pidfile ${XLDEVD_PIDFILE} ${XLDEVD_ARGS}
 
 	printf "\n"
 }