Notice in the example that the tag does not have the type="text/javascript" attribute. For some reason Rocket Loader requires data-cfasync="false" to be used without the type="text/javascript"… a bug?
Your code does add the data-cfasync="false" attribute, but does not override the WordPress behaviour of adding the type="text/javascript" attribute also, which makes Rocket Loader not to “ignore” your script.
It might be tricky to override this WordPress behaviour since the relevant code does not support a filter…