DB models don't set charset for individual tables

[Roman Prykhodchenko]

Tables should specify charset for MySQL in order to use UTF8. Now the stuff works because the charset is enforced by migration scripts.

However, the new feature of generating tables from models was introduced and it sets the default encoding to latin which will cause problems in production environments.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/111402

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/111402
Committed: https://git.openstack.org/cgit/openstack/ironic/commit/?id=35d46574ba6264089f26dfba0e6c083548d472e7
Submitter: Jenkins
Branch: master

commit 35d46574ba6264089f26dfba0e6c083548d472e7
Author: Roman Prykhodchenko <email address hidden>
Date: Sat Aug 2 01:06:13 2014 +0300

    Add charset and engine settings to every table

    Each MySQL table requires setting a default charset and engine,
    otherwise default values are used. It all worked previously because
    migration scripts enforce those values to the correct ones. Since
    we want to be able to generate the schema from models, those MySQL
    specific parameters must be set.

    This patch reuses a table_args() function that is already defined.

    Closes-bug: #1351431
    Change-Id: I3dafed9dfe5042fab1cff2ea029ea62c5e5cbea3