Block: Set bottom_snap_path when ready

[manuq]

The bottom_snap must be set on ready, regardless of previously setting it.

Regression from 9aae2bb

Fixes: #172

[dbnicholson]

Thanks. I'm still getting confused on when variables are set by Godot. I suppose that what's happening is that the node hasn't been added to the scene yet, so the initial get_node_or_null returns null.