logstash refuses to stop and exit, gets stuck

logstash-2.2.2, elasticsearch-1.7.5, java-1.8.0_72-b15, ubuntu-14.04 64bit, couchdb-1.6.1

```
input {
couchdb_changes {
always_reconnect => true
db => "vendnext_new_no_auth"
heartbeat => 5000
host => "couch31-prod-uswest2-aws.domain"
port => 5984
reconnect_delay => 10
}
}
filter {
mutate {
remove_field => [ "stripe", "moneris", "roles", "_rev", "freeVendUses", "surcharge", "debugMessages" ]
convert => [ "[doc][debugMessages]", "string"]
}
}
output {
elasticsearch {
action => "index"
hosts => "localhost:9200"
index => "vendnext_new_no_auth_index"
manage_template => false
script => "domain-filter"
script_lang => "javascript"
script_type => "file"
}
}
```

Overall it appears to work just fine. But the problems begin when I try to stop it.

"service logstash stop" stops the updates, but the logstash process does not quit. Repeating "service logstash stop" makes no difference. Logstash appears to be frozen - no updates sent to ElasticSearch, but it does not quit either.

After that, "service logstash status" reports the service as still running.

"kill $PID" doesn't kill it. The only way to kill it is "kill -9 $PID".