Suggested release note text:
Shutting down a ClusterEnvironment now correctly stops a `Meter` owned by the cluster. This plugs a resource leak where `LoggingMeter` worker threads would never be stopped.
Shutting down the cluster environment should stop the meter if the meter is owned by the environment, but this wasn't happening.
|For Gerrit Dashboard: JVMCBC-1077|
|172726,2||JVMCBC-1077 CoreEnvironment.shutdown doesn't stop owned Meter||master||couchbase-jvm-clients||Status: MERGED||+2||+1|
|173797,2||JVMCBC-1077 CoreEnvironment.shutdown doesn't stop owned Meter||hopper||couchbase-jvm-clients||Status: MERGED||+2||+1|