I'm getting some unexpected fields in the message content when sending a List message using JMS client to nodejs/rhea peer. I believe that is not expected.

Only list messages are affected, other message types do not suffer from that.

Steps to reporoduce:
1. run cli-rhea listener [1]
2. send a JMS list message using cli-qpid-jms [2]
3. print the received message content, see unexpected fields (typecode, multiple) and note that the content is nested (the actual content might be accessed by message['body']['content'] that is not expected).

[1] https://www.npmjs.com/package/cli-rhea
[2] https://github.com/rh-messaging/cli-java

# cli-rhea-receiver --log-msgs body --recv-listen true
{"typecode":118,"content":["foo","bar"],"multiple":None}

# java  -jar aac1.jar sender --msg-content-list-item "foo" --msg-content-list-item "bar"