JRuby misses iconv extension

This has been found while updating ruby-mp3info to version 0.7.1, as the tests fail when they try to convert to utf16, the problem should be this code:

def self.ruby_18_encode(from, to, value)
begin
Iconv.iconv(to, from, value).first
rescue Iconv::Failure
value
end
end

Of course it should be easier when moving to 1.7 which iirc defaults to Ruby 1.9 syntax.