[OPENENGSB-3416] remove unused api-reference
[OPENENGSB-3416] remove unused api-reference

openengsb/openengsb,openengsb-attic/openengsb-edb-api,openengsb/openengsb,openengsb/openengsb,openengsb/openengsb,openengsb/openengsb,openengsb/openengsb