PROTON-2015: [cpp] listener::on_error() should throw by default
PROTON-2015: [cpp] listener::on_error() should throw by default

ssorj/qpid-proton,apache/qpid-proton,ssorj/qpid-proton,kgiusti/qpid-proton,astitcher/qpid-proton,ssorj/qpid-proton,ChugR/qpid-proton,ssorj/qpid-proton,astitcher/qpid-proton,ChugR/qpid-proton,ChugR/qpid-proton,kgiusti/qpid-proton,apache/qpid-proton,apache/qpid-proton,ChugR/qpid-proton,kgiusti/qpid-proton,gemmellr/qpid-proton,apache/qpid-proton,astitcher/qpid-proton,kgiusti/qpid-proton,gemmellr/qpid-proton,ChugR/qpid-proton,gemmellr/qpid-proton,kgiusti/qpid-proton,ssorj/qpid-proton,gemmellr/qpid-proton,astitcher/qpid-proton,kgiusti/qpid-proton,apache/qpid-proton,gemmellr/qpid-proton,astitcher/qpid-proton,ChugR/qpid-proton,ssorj/qpid-proton,gemmellr/qpid-proton,apache/qpid-proton,astitcher/qpid-proton