PROTON-624: reset BytesMessage after reading body in JMSMappingOutboundTransformer

Applied patch from Jesse Fugitt.

git-svn-id: https://svn.apache.org/repos/asf/qpid/proton/trunk@1611094 13f79535-47bb-0310-9956-ffa450edef68
PROTON-631: avoid NPE in InboundTransformer if the 'x-opt-jms-type' message annotation was set with a null value rather than being ommitted

Applied patch from Timothy Bish.

git-svn-id: https://svn.apache.org/repos/asf/qpid/proton/trunk@1611095 13f79535-47bb-0310-9956-ffa450edef68