You can't really control logging in that way. You have control over whether to log INFO, WARN, ERROR etc, but within that category if a "server" event happens then that will get logged at whatever priority you've set in your rootCategory.
and this will suppress all "INFO" level log entries.
However this is not something I would advise. If you do experience issues with Wowza then the default log settings are very important in helping us to understand what was happening in your environment at the time of the problem.