[queues/mongodb] Use a single namespace for catalogue and shards DBs

[Allele Dev]

Just as the name says. Instead of using:

    @property
    def shards_database():

    @property
    def catalogue_database():

Just use self.mongo_conf.database directly.

[Zhihao Yuan (zyuan)]

+1

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/64719

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/64719
Committed: https://git.openstack.org/cgit/openstack/marconi/commit/?id=1d47c602b0cfb3e68226bef05ae7af05cfb97155
Submitter: Jenkins
Branch: master

commit 1d47c602b0cfb3e68226bef05ae7af05cfb97155
Author: cpallares <email address hidden>
Date: Thu Jan 2 13:49:40 2014 -0600

    Change shards & catalogue db into single property

    Refactoring the shards and catalogue mongo database methods into a
    single method because there's no need for these to access different
    logical databases.

    Change-Id: Ia75df73dcdb31e88473878f6c55abcf159f1aa44
    Closes-Bug: #1246373