Code review comment for ~mertkirpici/juju-lint:lp/2009536

I think I didn't understand completely what we are trying to achieve here.

IMO the bug is a corner case where an `optional` charm in the deployment is subordinate and can be deployed more than once in a machine. E.g: when relating to a principal and another subordinate charm.

My questions are:

- Can rsyslog-forwarder-ha be deployed more than once in a machine?
- If it can, I'm guessing that we will jump from KeyError to juju-lint error?
- Don't we need to change the rules file to accept this corner case with rsyslog-forwarder-ha?

Having at least an unit test covering this corner case is important.

Thanks