Werk #4207: mk_jolokia: Use configured port as default instance name

Previously, the mk_jolokia plugin would default to the port as an instance name if no name was configured before reading the config file. This led to the default instance name always being 8080, regardless of which port was actually configured.

If you have configured a nonstandard port in jolokia.cfg, but not an instance name, rediscovery is required, as well as adjusting rules relying on the instance name.

To the list of all Werks