busybox: Fix cron log level to match previous behavior

busybox: Fix cron log level to match previous behavior

Change the cron log level in init script from 5 to 7
in order to match previous log behavior and to avoid
log spam every minute.

Busybox cron only uses levels 5,7,8, where 5 is debug and
7 and 8 are normal logging. Use 7 as default.

(Fun note: this is needed because upstream corrected an
ancient bug in their own log level handling and now 5 actually
means something.)

Signed-off-by: Hannu Nyman <hannu.nyman@iki.fi>
Link: https://github.com/openwrt/openwrt/pull/17107
Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>