tools: xencommons init script: Fix setting XENSTORED_ROOTDIR

Due to a logic bug, XENSTORED_ROOTDIR was not being set to
default value when zero length.

Signed-off-by: Jim Fehlig <jfehlig@suse.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
Committed-by: Ian Jackson <ian.jackson@eu.citrix.com>

tools/hotplug/Linux/init.d/xencommons

@@ -61,7 +61,7 @@ do_start () {
 
 	if ! `xenstore-read -s / >/dev/null 2>&1`
 	then
-		test -z "$XENSTORED_ROOTDIR" || XENSTORED_ROOTDIR="/var/lib/xenstored"
+		test -z "$XENSTORED_ROOTDIR" && XENSTORED_ROOTDIR="/var/lib/xenstored"
 		rm -f "$XENSTORED_ROOTDIR"/tdb* &>/dev/null
 		test -z "$XENSTORED_TRACE" || XENSTORED_ARGS=" -T /var/log/xen/xenstored-trace.log"