Disable rsyslog logging for ST2 services

If you find an issue in packages, please file an issue and we'll have a look as soon as we can.
In order to expedite the process, it would be helpful to follow this checklist and provide
relevant information.

• [ CentOS Linux release 7.3.1611 (Core) ] Operating system: uname -a, ./etc/lsb_release or cat /etc/redhat-release
• [st2 2.6.0 ] StackStorm version: st2 --version
• [All st2 services ] Actual package versions of all packages (st2, st2web, st2chatops, st2mistral, nginx, mongo, rabbitmq-server, postrgresql; Enterprise: st2flow, st2-auth-ldap)

Issue details

I have noticed in our ST2 instance that rsyslog messages log file is flooded by st2 services. All the execution results are logged in their own st2 log files in /var/log/st2 and /var/log/messages.

Since each st2 service is configured with the dedicated log file, rsyslogd shouldn't be used for logging. This is causing disk space problem in our production instance as the logs are written redundantly in 2 places.

Can you please disable the ST2 default logging to rsyslog? This can be further manually enabled if something needed in future.

cat /etc/rsyslog.d/* /etc/rsyslog.conf | grep '/var/log/messages'
*.info;mail.none;authpriv.none;cron.none                /var/log/messages

Start by tracing the package configuration for all ST2 services and the rsyslog settings under /etc/rsyslog.d and /etc/rsyslog.conf. Compare the service logs in /var/log/st2 with /var/log/messages and check how the packages configure logging. Done means normal ST2 execution results are no longer duplicated in the rsyslog destination while dedicated service logs still work.