ports/111209: Undefined variable RUBY_PORTEPOCH is referenced in Makefile of some ruby sub-ports.

[KIMURA Yasuhiro]

Bad news. I updated my port tree and found the problem still
exists. And there was also a report at freebsd-ports ML. It seems
there is nothing to keep the idea of RUBY_PORTEPOCH variable from
working well, but anyway PORTEPOCH of these ports (and that of
lang/ruby18) is still set to zero...