appservice-irc doesn't have permission to create files in its project
directory and the intention is to log to the console, anyway. By
commenting out the file names, appservice-irc won't attempt to open the
files.
Currently the nginx reload cron fails on Debian 9 because the path to
systemctl is /bin/systemctl rather than /usr/bin/systemctl.
CentOS 7 places systemctl in both /bin and /usr/bin, so we can just use
/bin/systemctl as the full path.
This allows overriding the default value for `include_content`. Setting
this to false allows homeserver admins to ensure that message content
isn't sent in the clear through third party servers.