Fixed issue with unresolved symbols at runtime for DeliveryMode constants.
Fixed issue with unresolved symbols at runtime for DeliveryMode constants.

winking324/pyactivemq,hetian9288/pyactivemq,chenrui333/pyactivemq,cleardo/pyactivemq,aberzan/pyactivemq,winking324/pyactivemq,haofree/pyactivemq,hetian9288/pyactivemq,alberts/pyactivemq,alberts/pyactivemq,aberzan/pyactivemq,haofree/pyactivemq,cleardo/pyactivemq,WilliamFF/pyactivemq,chenrui333/pyactivemq,cl2dlope/pyactivemq,WilliamFF/pyactivemq,cl2dlope/pyactivemq