There can be issues during database migrations when a column used as a
foreign key is using a different collation between the parent and
child table.
Update the my.cnf template to set the server default collation to
utf8_general_ci to ensure consistency between tables initially
created with and those later altered to use the utf8 character set.
This matches both the instruction from the OpenStack install guide[0],
and MariaDB's default for the utf8 character set[1].
[0]
http://docs.openstack.org/mitaka/install-guide-ubuntu/environment-sql-database.html
[1]
> SHOW CHARACTER SET WHERE CHARSET = 'utf8';
+---------+---------------+-------------------+--------+
| Charset | Description | Default collation | Maxlen |
+---------+---------------+-------------------+--------+
| utf8 | UTF-8 Unicode | utf8_general_ci | 3 |
+---------+---------------+-------------------+--------+
Related-Bug: 1594195
Change-Id: I8507b6c9bd058bb308cc089f3802e52e24bea324
ac3942da3d