Unrelated parameters in the config

[zheyuye]

There are a lot of irrelevant or unsed parameters in the configuration file such as
pooler_fc_size, pooler_num_attention_heads, pooler_size_per_head, pooler_type. It's even more remarkable that type_vocab_size is set to be 2 in the config. This is in complete conflict with the idea that the Roberta model does not use Token Type Embedding.