Screwdriver: disallow rotation with on_rotate = false

Other screwdriver mods, or mods that cause rotation, might operate without the screwdriver mod loaded and have `screwdriver.disallow` unavailable.
This allows nodes to default to full-disallow rather than full-rotation in such a situation.

mods/screwdriver/init.lua

@@ -64,6 +64,7 @@ screwdriver.handler = function(itemstack, user, pointed_thing, mode, uses)
 		end
 	else
 		if not ndef or not ndef.paramtype2 == "facedir" or
+				ndef.on_rotate == false or
 				(ndef.drawtype == "nodebox" and
 				not ndef.node_box.type == "fixed") or
 				node.param2 == nil then