Update lua.test to pass on Mac OS X (minor issue with fiber id).

test/box/lua.test

@@ -153,7 +153,7 @@ exec admin "lua old_id = f:id()"
 exec admin "lua box.fiber.cancel(f)"
 exec admin "lua box.fiber.self():id() - old_id < 3"
 exec admin "lua box.fiber.cancel(box.fiber.self())"
-exec admin "lua box.fiber.self():id() - old_id < 4"
+exec admin "lua box.fiber.self():id() - old_id < 5"
 exec admin "lua g = box.fiber.self()"
 exec admin "lua f==g"
 exec admin "lua function r() f = box.fiber.create(r) return (box.fiber.resume(f)) end"