Fix debug logging of consumed outgoing messages so that the logged message is a string and a not a TransportUserMessage.
Fix debug logging of consumed outgoing messages so that the logged message is a string and a not a TransportUserMessage.

vishwaprakashmishra/xmatrix,harrissoerja/vumi,harrissoerja/vumi,TouK/vumi,vishwaprakashmishra/xmatrix,TouK/vumi,TouK/vumi,harrissoerja/vumi,vishwaprakashmishra/xmatrix