aix watchdog can create enough noise to fill out a partition, cron entry should have output redirection

the cronjob for the aix watchdog shell script is is created without output redirection (>/dev/null 2>&1), therefore script outputs resulting in cron mail flooding, which filled up our /var filesystem (mail spool).

https://github.com/cfengine/masterfiles/blob/master/cfe_internal/core/watchdog/watchdog.cf#L186