db_sync with oauth1 extension fails

When running with DB2, migration 4 for the oauth1 extension fails with an error:

2014-02-25 11:23:40.185 CRITICAL keystone [-] ProgrammingError: (ProgrammingError) ibm_db_dbi::ProgrammingError: Statement Execute Failed: [IBM][CLI Driver][DB2/LINUXX8664] SQL0205N Column, attribute, or period "REQUESTED_ROLES" is not defined in "KEYSTONE.REQUEST_TOKEN". SQLSTATE=42703 SQLCODE=-205 '\nALTER TABLE request_token ALTER COLUMN requested_roles DROP NOT NULL' ()

So it's saying the column doesn't exist for the alter table when making the column nullable.

Here's the code:

    request_token_table.c.requested_roles.alter(name="role_ids", nullable=True)

It looks like what's happening is that sqlalchemy is doing the name change first and then doing the "nullable=True" change with the original name and not the new one.