Error importing frequency_response results from database to csvs

`frequency_response_partial_reserve_provision_mw` should be `frequency_response_partial_reserve_provision` in `https://github.com/blue-marble/gridpath/blob/develop/db/db_schema.sql`

Error importing to `project_timepoints.csv`. Column name is `frequency_response_partial_reserve_provision`, `frequency_response_partial_reserve_provision_mw` does not exists