Initialise notification byte
Initialise notification byte

Avoids memory checker warning (drmemory) about reading an uninitialised
byte.

rgrinberg/lwt,rneswold/lwt,rgrinberg/lwt,rgrinberg/lwt,rneswold/lwt,c-cube/lwt,rneswold/lwt,mirage/lwt,c-cube/lwt,mfp/lwt,mirage/lwt,ocsigen/lwt,fdopen/lwt,fdopen/lwt,mfp/lwt,rgrinberg/lwt,ocsigen/lwt,c-cube/lwt,ocsigen/lwt