Interface out all action log data model operations

This will allow us to reimplement the logs data model against a non-database system in the near future

endpoints/keyserver/models_interface.py

@@ -63,10 +63,3 @@ class KeyServerDataInterface(object):
     Deletes and returns a service key with the given kid or raises ServiceKeyNotFound.
     """
     pass
-
-  @abstractmethod
-  def log_action(self, action_name, ip, metadata_dict=None):
-    """
-    Records a particular serivce key interaction to an audit log.
-    """
-    pass