修复部分代码风格的问题

oj/server_settings.py

@@ -36,13 +36,6 @@ REDIS_QUEUE = {
     "db": 2
 }
 
-
-# for celery
-BROKER_URL = 'redis://%s:%s/%s' % (REDIS_QUEUE["host"], str(REDIS_QUEUE["port"]), str(REDIS_QUEUE["db"]))
-CELERY_ACCEPT_CONTENT = ["json"]
-CELERY_TASK_SERIALIZER = "json"
-
-
 DEBUG = False
 
 ALLOWED_HOSTS = ['*']