Inconsistency attribute and checking conditions.

[Ilya Pekelny]

In https://github.com/openstack/oslo-incubator/blob/master/tests/unit/db/sqlalchemy/base.py#L146 defined an attribute "postgresql". In https://github.com/openstack/oslo-incubator/blob/master/tests/unit/db/sqlalchemy/base.py#L111 the attribute used to compile connection string by `_get_connect_string` from `common/db/sqlalchemy/test_migrations.py`. In https://github.com/openstack/oslo-incubator/blob/master/openstack/common/db/sqlalchemy/test_migrations.py#L40 `_get_connect_string ` obvious wait for "postgres" argument.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/59347

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/59347
Committed: https://git.openstack.org/cgit/openstack/oslo-incubator/commit/?id=9a203e6f5d17cbb1a46778b51d7e8a026d0ae919
Submitter: Jenkins
Branch: master

commit 9a203e6f5d17cbb1a46778b51d7e8a026d0ae919
Author: Ilya Pekelny <email address hidden>
Date: Mon Dec 2 12:18:18 2013 +0200

    Use dialect rather than a particular DB API driver

    _get_connect_string() is too specific when choosing a DB API driver to be
    used. We shouldn't force users to use neither psycopg2 nor MySQLdb as this is
    not required for any actions provided by oslo.db. Specify only the dialect to
     be used and let SQLAlchemy choose one of the DB API drivers available.

    Closes-Bug: #1256835
    Change-Id: I685f9eecc77f2c1f920c83c5da653f3114a83679