mpi/tests/: use MPI_STATUS_IGNORE instead of NULL to indicate to MPI_Wait to ignore the status

mpi/tests/mpi_earlyrecv.c

@@ -57,7 +57,7 @@ int main(int argc, char **argv)
 	if (rank%2)
 	{
 		starpu_mpi_isend(tab_handle[0], &request[0], other_rank, 0, MPI_COMM_WORLD);
-		starpu_mpi_recv(tab_handle[2], other_rank, 2, MPI_COMM_WORLD, NULL);
+		starpu_mpi_recv(tab_handle[2], other_rank, 2, MPI_COMM_WORLD, MPI_STATUS_IGNORE);
 		starpu_mpi_isend(tab_handle[1], &request[1], other_rank, 1, MPI_COMM_WORLD);
 		nb_requests = 2;
 	}

mpi/tests/mpi_earlyrecv2.c

@@ -99,7 +99,7 @@ int exchange(int rank, starpu_data_handle_t *handles, check_func func, int detac
 		{
 			for(i=0 ; i<NB ; i++)
 			{
-			     starpu_mpi_wait(&req[i], NULL);
+			     starpu_mpi_wait(&req[i], MPI_STATUS_IGNORE);
 			     func(handles[i], i, rank, &ret);
 			}
 		}