Fix: use dropout layer

pytorch_pretrained_bert/modeling_openai.py

@@ -374,6 +374,7 @@ class OpenAIGPTMultipleChoiceHead(nn.Module):
         # (bsz, num_choices, 1, hidden_size)
         multiple_choice_h = hidden_states.gather(2, mc_token_ids).squeeze(2)
         # (bsz, num_choices, hidden_size)
+        multiple_choice_h = self.dropout(multiple_choice_h.transpose(1, 2)).transpose(1, 2)
         multiple_choice_logits = self.linear(multiple_choice_h).squeeze(-1)
         # (bsz, num_choices)
         return multiple_choice_logits