mpi: add missing interface data

mpi/starpu_mpi_datatype.c

@@ -121,7 +121,8 @@ static handle_to_datatype_func handle_to_datatype_funcs[STARPU_NINTERFACES_ID] =
 	[STARPU_BLOCK_INTERFACE_ID]	= handle_to_datatype_block,
 	[STARPU_VECTOR_INTERFACE_ID]	= handle_to_datatype_vector,
 	[STARPU_CSR_INTERFACE_ID]	= NULL,
-	[STARPU_BCSR_INTERFACE_ID]	= NULL
+	[STARPU_BCSR_INTERFACE_ID]	= NULL,
+	[STARPU_VARIABLE_INTERFACE_ID]	= NULL
 };
 
 static handle_to_ptr_func handle_to_ptr_funcs[STARPU_NINTERFACES_ID] = {
@@ -129,7 +130,8 @@ static handle_to_ptr_func handle_to_ptr_funcs[STARPU_NINTERFACES_ID] = {
 	[STARPU_BLOCK_INTERFACE_ID]	= handle_to_ptr_block,
 	[STARPU_VECTOR_INTERFACE_ID]	= handle_to_ptr_vector,
 	[STARPU_CSR_INTERFACE_ID]	= NULL,
-	[STARPU_BCSR_INTERFACE_ID]	= NULL
+	[STARPU_BCSR_INTERFACE_ID]	= NULL,
+	[STARPU_VARIABLE_INTERFACE_ID]	= NULL
 };
 
 int starpu_mpi_handle_to_datatype(starpu_data_handle data_handle, MPI_Datatype *datatype)