pitchfork clones dirt

[fluxionary]

When you dig a dirt-with-grass node with the pitchfork,

1. You pick up a dirt node in your inventory.
2. The dirt-with-grass node you dug turns into a dirt node.
3. Hay spawns on top of the dirt node.

My feeling is that (1) shouldn't happen. If that's too hard, (2) shouldn't happen.

This is tested w/ minetest 5.0.1 w/ a survival player on a public server.

[orbea]

Just linking the related PR here. :)

#12