mail-filter/spamassassin: new revision letting spamd run as root (systemd).

mail-filter/spamassassin: new revision letting spamd run as root (systemd).

In the previous revision (r18), support was added for running spamd as
root through OpenRC. That was done using a new variable called
SPAMD_RUN_AS_ROOT, defaulting to false. The choice to use a boolean
variable -- as opposed to e.g. SPAMD_USER -- was made because passing
"root" as the username to spamd kills it. Thus, SPAMD_USER=root would
not have worked, and we instead test SPAMD_RUN_AS_ROOT to decide
whether or not to specify a username/groupname at all.

The same exact issue arises with systemd; however, systemd offers no
way for us to test the value of SPAMD_RUN_AS_ROOT and act on the
result! The SPAMD_USER proposal is dead in the water for the same
reason, so a different approach was needed. The simplest thing that
could work was to move the "--username" and "--groupname" flags out
of the systemd service file, and into the SPAMD_OPTS variable. That
way, users who know what they are doing can simply drop those flags.

Closes: https://bugs.gentoo.org/635790
Package-Manager: Portage-2.3.8, Repoman-2.3.3