remove Spawner.fromJSON

load state on `__init__` instead

Makes more sense now that state can persist
across server instances (e.g. docker container_id)

jupyterhub/orm.py

@@ -305,13 +305,17 @@ class User(Base):
         api_token = self.new_api_token()
         db.add(api_token)
         db.commit()
-
+        
+        
         spawner = self.spawner = spawner_class(
             config=config,
             user=self,
             hub=hub,
             api_token=api_token.token,
         )
+        # we are starting a new server, make sure it doesn't restore state
+        spawner.clear_state()
+        
         yield spawner.start()
         spawner.start_polling()
 
@@ -335,6 +339,7 @@ class User(Base):
         status = yield self.spawner.poll()
         if status is None:
             yield self.spawner.stop()
+        self.spawner.clear_state()
         self.state = self.spawner.get_state()
         self.last_activity = datetime.utcnow()
         self.server = None