Discount is still set when Regular Fees were configured as part of prices set

If discount is configured for an event and Regular Fees is configured as part of a Price Set, with the added flexibility and complexity that entails. The discount is still not being deleted from civicrm_discount.

To replicate:
1. Create event.
2. Enable fee and add discount with now() date and save.
3. click on "click here" in Regular fees section. i.e convert regular fees into price set.
4. Now register participant for event.

The discount is still set even if regular fees are still converted to price set.