Don't assume the queue controller is in the same storage

[Flavio Percoco]

Some parts of the storage drivers assume the queue_controller is in the same storage as the other parts are. For example, the subscription implementation for mongodb has this init:

    def __init__(self, *args, **kwargs):
        super(SubscriptionController, self).__init__(*args, **kwargs)
        self._collection = self.driver.subscriptions_database.subscriptions
        queue_col = self.driver.control_driver.queues_database.queues
        self._queue_collection = queue_col
        self._collection.ensure_index(SUBSCRIPTIONS_INDEX, unique=True)

There, it gets the database instance and the collection instance, which is wrong. It should never assume the queue controller is on top of mongodb. This applies to other parts as well

[Flavio Percoco (flaper87)]

https://review.openstack.org/#/c/205856/ approved

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/205856
Committed: https://git.openstack.org/cgit/openstack/zaqar/commit/?id=a909fab7e3e3746d4372284e117b251b36553702
Submitter: Jenkins
Branch: master

commit a909fab7e3e3746d4372284e117b251b36553702
Author: Fei Long Wang <email address hidden>
Date: Mon Jul 27 12:17:19 2015 +1200

    Decouple the queue and subscription

    Now some parts of the subscription storage drivers is assuming
    the queue_controller is in the same storage. But unfortunately,
    it's not always true. This patch fixes it, but there is no new
    test case involved.

    Closes-Bug: #1471193

    Change-Id: Ic81c928657addd4e0905c3af2b3c8321017559f5