Repairing items is a little broken

Put the summary of the bug you're having here

What I expected to happen was when I repair a renamed item in an anvil, I expected the level cost to stay the same, like in 1.7.x and before

What actually happened was the cost got greater every time, as if the item wasn't renamed.

Steps to Reproduce:
1.rename an item
2.damae it
3.repair it and keep in mind the level cost
4.damage it again
5.repair it and look at the level cost. It will be greater than before.