only start crond if there are files in the crontab

SVN-Revision: 10292

package/busybox/files/cron

@@ -3,6 +3,7 @@
 START=50
 
 start () {
+	[ -z $(ls /etc/crontabs/) ] && exit 1
 	mkdir -p /var/spool/cron
 	[ -L /var/spool/cron/crontabs ] || ln -s /etc/crontabs /var/spool/cron/crontabs
 	crond -c /etc/crontabs