We don't need to set $TZ, because we have /etc/localtime. In fact,
setting $TZ without $TZDIR doesn't work anymore since Glibc no longer
contains zone info.
When spamd isn't running as 'root', it cannot access the usual ~/.spamassassin
path where user-specific files normally reside. Instead, we use the path
/var/lib/spamassassin-<user> to store those home directories.
