add checker for hetero_nn_param's drop_out_keep_rate
add checker for hetero_nn_param's drop_out_keep_rate

Signed-off-by: mgqa34 <873f6cae19e173e032060684f437bdb9a161fc74@163.com>

FederatedAI/FATE,FederatedAI/FATE,FederatedAI/FATE