Fix position of corner k,k tile MPI flush

mpi/examples/mpi_lu/pxlu_implicit.c

@@ -133,14 +133,14 @@ double STARPU_PLU(plu_main)(unsigned _nblocks, int _rank, int _world_size)
 	{
 		create_task_11(k);
 
-		starpu_mpi_cache_flush(MPI_COMM_WORLD, STARPU_PLU(get_block_handle)(k,k));
-
 		for (i = k+1; i<nblocks; i++)
 		{
 			create_task_12(k, i);
 			create_task_21(k, i);
 		}
 
+		starpu_mpi_cache_flush(MPI_COMM_WORLD, STARPU_PLU(get_block_handle)(k,k));
+
 		for (i = k+1; i<nblocks; i++)
 		{
 			for (j = k+1; j<nblocks; j++)