Putting an item frame into an item frame causes only one item frame to drop upon taking down the item frame.

Put the summary of the bug you're having here

What I expected to happen was...:
When I break an item frame displaying an item frame it should drop two item frames. Precedent being when an item frame holding any other item is broken it drops the frame AND the item.

What actually happened was...:
When I break the item frame displaying an item frame it only drops one item frame, resulting in a loss of one item frame.

Steps to Reproduce:
1. Place an item frame on a wall.
2. Put an item frame in the item frame.
3. Break the item frame displaying the item frame.