busybox: prevent globbing, word splitting

Double quote to prevent globbing and word splitting.

Signed-off-by: Jan-Tarek Butt <tarek@ring0.de>

package/utils/busybox/files/cron

@@ -14,7 +14,7 @@ validate_cron_section() {
 start_service () {
 	[ -z "$(ls /etc/crontabs/)" ] && return 1
 
-	loglevel=$(uci_get "system.@system[0].cronloglevel")
+	loglevel="$(uci_get "system.@system[0].cronloglevel")"
 
 	[ -z "${loglevel}" ] || {
 		/sbin/validate_data uinteger "${loglevel}" 2>/dev/null
@@ -28,7 +28,7 @@ start_service () {
 	ln -s /etc/crontabs /var/spool/cron/ 2>/dev/null
 
 	procd_open_instance
-	procd_set_param command "$PROG" -f -c /etc/crontabs -l ${loglevel:-5}
+	procd_set_param command "$PROG" -f -c /etc/crontabs -l "${loglevel:-5}"
 	procd_close_instance
 }