audit plugin can't see connections events if undefined log=file in my.cnf

We have tested it 5.5.28 as 5.5.31 is not out and 29 and 30 have regression for our workload

Hopefully it looks like <> issue from https://mariadb.atlassian.net/browse/MDEV-258

Using filter GENERAL_CLASSMAX we did not catch connection events if log=some_file.log not defined in the my.cnf

Show variables like ‘general_log%’ was set to some default file name is not enouth
We only catch other events queries until we forced the log=general.log in the cnf file and restart

One more issue is that replication events are reported with an empty user / host that may cause issue with generic user@host blacklist and whitelist configuration file