Flora spread: Do not replace flora with dry shrub, only 'return'

If there is no group:soil node found below, do not replace flora with
dry shrub, this was breaking flower pots and other mods.
Originally, flora would only turn to dry shrub if in desert sand.

mods/flowers/init.lua

@@ -107,10 +107,9 @@ function flowers.flower_spread(pos, node)
 	pos.y = pos.y - 1
 	local under = minetest.get_node(pos)
 	pos.y = pos.y + 1
-	if minetest.get_item_group(under.name, "soil") == 0 and
-			-- Do not replace sand dune grasses
-			under.name ~= "default:sand" then
-		minetest.set_node(pos, {name = "default:dry_shrub"})
+	if minetest.get_item_group(under.name, "soil") == 0 then
+		-- Do not replace with dry shrub here as
+		-- this breaks flower pots and other mods.
 		return
 	end