Added RUBY_INSTALL_VERSION.
Added RUBY_INSTALL_VERSION.

ngpestelos/chruby,ngpestelos/chruby,eunomie/chgo,postmodern/chruby,postmodern/chruby,regularfry/chruby,regularfry/chruby,ilikepi/chruby,ilikepi/chruby,eunomie/chgo,kbrock/chruby,kbrock/chruby