Lava bucket doesn't smelt anything in the furnace.

**What I expected to happen was...:**

I wanted to smelt some cobblestone in furnace using a bucket of lava.

What actually happened was...:

• • Bucket of lava didn't act as a fuel, remained inactive in a fuel slot in the furnace and didn't smelt any of the cobblestone. Extra info: I tried using coal, that worked.

Steps to Reproduce:

1. Insert cobblestone into the furnace in the upper slot.
2. Insert lava bucket in the lower slot in the furnace.
3. The furnace doesn't treat the bucket as a "burnable" item.