Comment 2 for bug 1435592

Reviewed: https://review.openstack.org/167032
Committed: https://git.openstack.org/cgit/stackforge/congress/commit/?id=c960d8e822f4f7b248c1d87abee721fae0684f3d
Submitter: Jenkins
Branch: master

commit c960d8e822f4f7b248c1d87abee721fae0684f3d
Author: Tim Hinrichs <email address hidden>
Date: Mon Mar 23 15:05:11 2015 -0700

    Disallow deletion of datasource if dangling references

    Previously, you could delete a datasource even if there
    were policy statements referencing the tables in that
    datasource.

    This change ensures it is impossible to delete a datasource
    if you still have references to that table provided by that
    datasource. This change fixes a bug where Congress
    fails to start because it does not have a schema for the
    rules contained in the database, which can only happen
    if the user has deleted the datasource with rules that
    still reference it.

    Closes-bug: 1435592
    Change-Id: I040f2829fc284b1ddb954b757cea886a498171b4