return 404 when translating empty evidence results
return 404 when translating empty evidence results

refs #44

OpenBEL/openbel-server,OpenBEL/openbel-server,OpenBEL/openbel-api,OpenBEL/openbel-api,nbargnesi/openbel-server,OpenBEL/openbel-server,OpenBEL/openbel-api,nbargnesi/openbel-server,nbargnesi/openbel-server,OpenBEL/openbel-api