add traceback to protocol decode
add traceback to protocol decode

addresses a FIXME: log a traceback on a decode exception

benagricola/exabgp,blablacar/exabgp,blablacar/exabgp,dneiter/exabgp,dneiter/exabgp,earies/exabgp,benagricola/exabgp,dneiter/exabgp,earies/exabgp,benagricola/exabgp,blablacar/exabgp,earies/exabgp