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).

Reference: https://lists.freebsd.org/pipermail/svn-ports-all/2019-March/209423.html

		https://github.com/sparklemotion/nokogiri/blob/v1.10.3/ext/nokogiri/extconf.rb#L447-L471