add pycurl to requirements

it's needed by kombu 4.0.2.

Also moved import about

app/__init__.py

@@ -13,6 +13,7 @@ from notifications_utils.clients.redis.redis_client import RedisClient
 from notifications_utils import logging, request_id
 from werkzeug.local import LocalProxy
 
+from app.celery.celery import NotifyCelery
 from app.clients import Clients
 from app.clients.email.aws_ses import AwsSesClient
 from app.clients.sms.firetext import FiretextClient
@@ -25,11 +26,6 @@ DATETIME_FORMAT = "%Y-%m-%dT%H:%M:%S.%fZ"
 DATE_FORMAT = "%Y-%m-%d"
 
 db = SQLAlchemy()
-
-# avoid circular import by importing after db
-from app.celery.celery import NotifyCelery
-
-
 ma = Marshmallow()
 notify_celery = NotifyCelery()
 firetext_client = FiretextClient()