ignore files starting with . e.g. .ipynb_checkpoints (#819)

Summary:
.ipynb_checkpoints folder in models folders crashed the importlib
now there is a check for this
Pull Request resolved: https://github.com/fairinternal/fairseq-py/pull/819

Differential Revision: D16772192

Pulled By: myleott

fbshipit-source-id: 01c956aef4ed312bc7645c31c83dbf98af89d931

fairseq/models/__init__.py

@@ -123,7 +123,7 @@ def register_model_architecture(model_name, arch_name):
 models_dir = os.path.dirname(__file__)
 for file in os.listdir(models_dir):
     path = os.path.join(models_dir, file)
-    if not file.startswith('_') and (file.endswith('.py') or os.path.isdir(path)):
+    if not file.startswith('_') and not file.startswith('.') and (file.endswith('.py') or os.path.isdir(path)):
         model_name = file[:file.find('.py')] if file.endswith('.py') else file
         module = importlib.import_module('fairseq.models.' + model_name)