Fix potionmaking XP

[Soxson]

Rare potions require an extra 15 lvls prereq on top of what the initial potion says it does. But when you actually make the potion, you don't get xp an uncommon potion of the same requirement would.

Example; I've been making r5 pilgrimage pots. It says it needs 35 potionmaking when it's actually 50. When I make the pots, I only get xp counting towards making a 35 prereq pot and since my actual potionmaking skill is higher than that, my xp is diminished.

Glitch, I know you're busy and probably have the next 2 years of projects planned out, but if you could take a look into this, I would greatly appreciate this. Devil in civil also strongly supports this.