Config file hardcoded in the error message

[Stanislaw Pitucha]

When connection is not defined, magnum-db-manage will fail with:

ValueError: Database connection not set in /etc/magnum/magnum.conf

even if it was explicitly run with --config-file /some/other/location

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/216090

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/216090
Committed: https://git.openstack.org/cgit/openstack/magnum/commit/?id=fb168ffb47e5b93df491a80248523d35757b51ca
Submitter: Jenkins
Branch: master

commit fb168ffb47e5b93df491a80248523d35757b51ca
Author: Lin Yang <email address hidden>
Date: Mon Aug 24 11:51:55 2015 +0800

    Remove hardcoded config file in error message

    Previously, it throw error message when database connection was
    not defined,

    "ValueError: Database connection not set in /etc/magnum/magnum.conf"

    even if it was explicitly run with "--config-file /other/location".
    So remove that hardcoded config file location.

    Change-Id: I3af00f1f6572c3cd9e56141e1774acf373bbce8b
    Closes-Bug: #1487258