more gracefully handle "Malformed IPv6 address" error #152
Description
Running the collector may result in an error like:
executing nodetool -h localhost -p 7199 **** status > nodetool/status.txt... nodetool: Failed to connect to 'localhost:7199' - URISyntaxException: 'Malformed IPv6 address at index 7: rmi://[localhost]:7199'.
This is introduced with Java8 u332, and resolved with https://issues.apache.org/jira/browse/CASSANDRA-17581 .
There are workarounds documented, e.g. https://datastaxcommunities.force.com/support/s/article/Malformed-IPv6-address-at-index-7-when-running-nodetool-and-dsetool
Ideally, the collector is able to work around this automatically without making changes to the target environment...perhaps noting that the environment has this error present.