Description of problem:
Message content-type property is not set using python spout. C++ and JMS clients sets the content-type on sending the message. All the clients shall behave the same way.
Version-Release number of selected component (if applicable):
Steps to Reproduce:
1. qpid-config add queue q
2. spout q "plain_text_message"
3. drain q
4. message property content-type is not set
Message content-type is not set
Appropriate content-type is set on sending the message with spout