scylla-jmx: Exit on unknown parameter rather than infinite-loop
scylla-jmx: Exit on unknown parameter rather than infinite-loop

Ran into this while trying to use ccm with not up-to-date scylla-jmx.

Symptoms:

  $ ccm start
  Error starting node node1

and empty ~/.ccm/scylla-3/node1/logs/system.log.jmx
Message-Id: <5e1b331e1b1d0c14a806b0324c8ac8fd0dd98f57@scylladb.com>

scylladb/scylla-jmx,scylladb/scylla-jmx,scylladb/scylla-jmx