message: Fix non-timeout condition when stream is already closed
diff: @@ -997,7 +997,7 @@ extern SstStatusValue SstAdvanceStep(SstStream Stream, int mode,
  {
  MPI_Bcast(&NextTimestep, 1, MPI_LONG, 0, Stream->mpiComm);
  }
  - if (Stream->Status == PeerClosed)
  + if ((NextTimestep == -1) && (Stream->Status == PeerClosed))
  {
  CP_verbose(Stream,
  "SstAdvanceStep returning EndOfStream at timestep %d\n",
  