updated fine-grained-ner-model-elmo URL (#2868)
updated fine-grained-ner-model-elmo URL (#2868)

Updated the model with the new one : fine-grained-ner-model-elmo-2018.08.31.tar.gz ->  fine-grained-ner-model-elmo-2018.12.21.tar.gz
allenai/allennlp,allenai/allennlp,allenai/allennlp,allenai/allennlp