Tests fail with mongo on driver setup

[Nataliia Uvarova]

With mongodb driver enabled, some tests fails with next error:

FAIL: tests.unit.queues.storage.test_impl_mongodb.MongodbPoolsTests.test_update_raises_assertion_error_on_bad_fields
tags: worker-0
----------------------------------------------------------------------
Empty attachments:
  pythonlogging:'marconi'
  stderr

Traceback (most recent call last):
  File "tests/unit/queues/storage/test_impl_mongodb.py", line 375, in setUp
    super(MongodbPoolsTests, self).setUp()
  File "marconi/tests/queues/storage/base.py", line 660, in setUp
    super(PoolsControllerTest, self).setUp()
  File "marconi/tests/queues/storage/base.py", line 61, in setUp
    self.controller = self.controller_class(self.driver)
  File "marconi/queues/storage/mongodb/pools.py", line 50, in __init__
    self._col = self.driver.database.pools
  File "marconi/common/decorators.py", line 146, in getter
    setattr(self, attr_name, fn(self))
  File "marconi/queues/storage/mongodb/driver.py", line 156, in database
    return self.connection[name]
  File "marconi/common/decorators.py", line 146, in getter
    setattr(self, attr_name, fn(self))
  File "marconi/queues/storage/mongodb/driver.py", line 151, in connection
    return _connection(self.mongodb_conf)
  File "marconi/queues/storage/mongodb/driver.py", line 39, in _connection
    if 'ssl=true' in conf.uri.lower():
AttributeError: 'NoneType' object has no attribute 'lower'

It looks like the problem appeared after https://review.openstack.org/100746

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/103307

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/103307
Committed: https://git.openstack.org/cgit/openstack/marconi/commit/?id=c5106bc26b824d9a8755fa88156f1de946dad878
Submitter: Jenkins
Branch: master

commit c5106bc26b824d9a8755fa88156f1de946dad878
Author: pengfei wang <email address hidden>
Date: Sat Jun 28 17:48:13 2014 +0800

    Add None checking for the Mongodb uri

    Change-Id: I9163c772d773ebecc51a88dc2280e8dba8ede009
    Closes-Bug: #1334750