Check for null last boot reason

webif/lib/bin/reboot

@@ -52,7 +52,9 @@ lbr=0
 if [ -f /tmp/.lbr ]; then
 	lbr="`cat /tmp/.lbr`"
 	#echo "LBR: $lbr"
-else
+	[ -z "$lbr" ] && lbr=0
+fi
+if [ $lbr -eq 0 ]; then
 	# No last-boot-reason file, fall-back to reading timer directly.
 	echo "No .lbr, falling back to timer..."
 	if readwakeup | grep "00 00 00 00"; then