title: Celery task routing doesn't work when using current_app.send_task
body: <p>I have an issue with Celery queue routing when using current_app.send_task </p>
  
  <p>I have two workers (each one for each queue)</p>
  
  <pre><code>python manage.py celery worker -E -Q priority --concurrency=8 --loglevel=DEBUG
  python manage.py celery worker -Q low --concurrency=8 -E -B --loglevel=DEBUG
  </code></pre>
  
  <p>I have two queues defined in celeryconfig.py file:</p>
  
  <pre><code># -*- coding: utf-8 -*-
  from __future__ import unicode_literals
  
  from django.core.exceptions import ImproperlyConfigured
  
  from celery import Celery
  from django.conf import settings
  
  try:
      app = Celery('proj', broker=getattr(settings, 'BROKER_URL', 'redis://'))
  except ImproperlyConfigured:
      app = Celery('proj', broker='redis://')
  
  app.conf.update(
      CELERY_TASK_SERIALIZER='json',
      CELERY_ACCEPT_CONTENT=['json'],
      CELERY_RESULT_SERIALIZER='json',
      CELERY_RESULT_BACKEND='djcelery.backends.database:DatabaseBackend',
      CELERY_DEFAULT_EXCHANGE='tasks',
      CELERY_DEFAULT_EXCHANGE_TYPE='topic',
      CELERY_DEFAULT_ROUTING_KEY='task.priority',
      CELERY_QUEUES=(
          Queue('priority',routing_key='priority.#'),
          Queue('low', routing_key='low.#'),
      ),
      CELERY_DEFAULT_EXCHANGE='priority',
      CELERY_IMPORTS=('mymodule.tasks',)
  
  CELERY_ENABLE_UTC = True
  CELERY_TIMEZONE = 'UTC'
  
  if __name__ == '__main__':
      app.start()
  </code></pre>
  
  <p>In the definition of tasks, we use decorator to explicit the queue:</p>
  
  <pre><code>@task(name='mymodule.mytask', routing_key='low.mytask', queue='low')
  def mytask():
      # does something
      pass
  </code></pre>
  
  <p>This task is run indeed in the low queue when this task is run using:</p>
  
  <pre><code>from mymodule.tasks import mytask
  mytask.delay()
  </code></pre>
  
  <p>But it's not the case when it's run using: (it's run in the default queue: "priority")</p>
  
  <pre><code>from celery import current_app
  current_app.send_task('mymodule.mytask')
  </code></pre>
  
  <p>I wonder why this later way doesn't route the task to the "low" queue!</p>
  
  <p>p.s: I use redis.</p>