Revert rubygem-mini_portile2 change in r502877
- Bump PORTREVISION for dependency change
We do not need mini_portile/mini_portile2. It was removed since r355100 and r494447.
mini_portile2 is used to download and build the libraries which is already handled by our ports framework very well.
Furthermore, it is not needed when using system libraries (CONFIGURE_ARGS=--use-system-libraries).