mail-filter/spamassassin: new revision with an optional sa-update cron job.

mail-filter/spamassassin: new revision with an optional sa-update cron job.

To make life easier for our users, a cron job that runs sa-update
nightly has been provided. It is only installed with USE=cron, but an
elog will mention its existence when that USE flag is disabled. The
cron job will also attempt to restart or reload spamd/amavisd if the
signatures have been updated.

Alongside that new feature, some of the dependencies have been cleaned
up. Pointless version bounds were removed, and an obsolete perl module
or two was pruned. The libwww-perl dependency was replaced by
wget/curl.

Gentoo-Bug: 532094

Package-Manager: portage-2.2.28