kalua: cron.patch_load_kmodules.sh: whitelist kmodule 'arc4' instead of blacklist it, the watchdog needs it on atheros-platform: https://dev.openwrt.org/ticket/12993
Revert "kalua: cron.patch_load_kmodules.sh: whitelist kmodule 'arc4' instead of blacklist it, the watchdog needs it on atheros-platform: https://dev.openwrt.org/ticket/12993"

This reverts commit af0888ce4a21d9263671c0c4adc063a8858bba72.
kalua: cron.patch_load_kmodules.sh: minor cleanup + log error during loading