Fix warning related to Hyper key definition

Fix warning present in KeyRemap4Macbook v8.3.19 [A] and later:

> Error in XML.
> ----------------------------------------
> You should not write <identifier> in <item> which has child <item> nodes.
> Remove <identifier>com.jasonrudolph.right_option_hyper</identifier>.
> ----------------------------------------

[A]: https://github.com/tekezo/KeyRemap4MacBook/commit/d35081eea2