Remove traces of aa-eventd
aa-eventd and its initscripts have been moved to deprecated/ in 2014 and didn't get any serious updates for several more years, so it's most probably useless and/or broken nowadays.
This also means we don't need to keep the AA_EV_BIN and AA_EV_PIDFILE variables in rc.apparmor.functions anymore.
(In theory I could move these variables to deprecated/rc.aaeventd.* - but in practise that sounds more than superfluous ;-)