sl4v & Nicu: Don't open chests if there is a full block above them, for 1-node normal & trapped chests

mods/ITEMS/mcl_chests/init.lua

@@ -227,6 +227,10 @@ minetest.register_node("mcl_chests:"..basename, {
 	_mcl_hardness = 2.5,
 
 	on_rightclick = function(pos, node, clicker)
+		if minetest.registered_nodes[minetest.get_node({x = pos.x, y = pos.y + 1, z = pos.z}).name].groups.opaque == 1 then
+			-- won't open if there is no space from the top
+			return false
+		end
 		local name = minetest.get_meta(pos):get_string("name")
 		if name == "" then
 			name = S("Chest")