Remove identifier from comment_base

Said identifier causes problems if a machine is accessed via multiple hostnames/addresses/etc., since whenever appears to create a new block of jobs in `crontab` for each hostname or address that's used to access the machine.  This causes duplication of jobs run (which causes problems with things like backup archive creation, since now there are two different jobs competing for the exact same resources to do the exact same thing).

This might be a bit heavy-handed, however.