I never had that error, but I had other rc.local
problems which led me to do this:
/etc/rc.d/rc.local just looks like:
/usr/bin/at -M now <<'HERE' > /dev/null 2>&1
/etc/rc.d/the-real-rc.local
HERE
touch /var/lock/subsys/local
Then /etc/rc.d/the-real-rc.local has all the stuff
I used to put in rc.local itself. This starts everything
outside the control of systemd, so it doesn't know
what started and can't make any dreadful assumptions
about what it should do with it.