title: django-rest-swagger 2.2.0 endpoints with auth classes not visible
body: <p>I'm developing a django application that has a bunch of endpoints that have custom and basic auth classes defined, but swagger shows only endpoints that don't have authentication classes and have a permission class = AllowAny.</p>
  
  <p><strong>How to make all endpoints be visible at 'docs/' endpoint without any authentications/permissions?</strong></p>
  
  <p><code>Django==2.1.7
  djangorestframework==3.9.1
  jango-rest-swagger==2.2.0</code></p>
  
  <p><code>REST_FRAMEWORK = {
      'DEFAULT_PERMISSION_CLASSES': (
          'rest_framework.permissions.AllowAny',
      ),
      'DEFAULT_AUTHENTICATION_CLASSES': (
          'rest_framework.authentication.SessionAuthentication',
      ),
      'DEFAULT_PARSER_CLASSES': (
          'rest_framework.parsers.JSONParser',
          'rest_framework.parsers.FormParser',
          'rest_framework.parsers.MultiPartParser',
      )
  }</code></p>
  
  <p><code>SWAGGER_SETTINGS = {
      'exclude_namespaces': [],  # List URL namespaces to ignore
      'api_version': '',  # Specify your API's version. Might be useful in future
      'api_path': '/',  # Specify the path to your API not a root level
      'enabled_methods': [  # Specify which methods to enable in Swagger UI
          'get',
          'post',
          'put',
          'patch',
          'delete'
      ],
      'token_type': 'Bearer',
      'api_key': {},  # An API key
      'is_authenticated': False,  # Set to True to enforce user authentication,
      'is_superuser': False,  # Set to True to enforce admin only access
  }</code></p>