- Fixed calculation of sleep duration; on some systems/IPs, `hostid`
        results in a negative number which is retained by the bash
        modulo-operation. So the sleep may get a negative number of seconds
        being interpreted as an option. This version makes sure that the
        module-operations returns a non-negative value. [BZ #164494, James
        Wilkinson]
    - added support for a /usr/sbin/clamav-notify-servers.local hook; this file
        will be executed (source'd) before all other actions and can abort the
        entire processing by invoking 'exit'