PROTON-1766: [c] Fix missing NULL check in epoll proactor
PROTON-1766: [c] Fix missing NULL check in epoll proactor

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