Ignore broken test on 2.1.1 and 2.1.2

Closes #26

It's a Ruby issue that they fixed but hasn't been released yet.

Example  here: https://gist.github.com/JoshCheek/8aee8ef4a5f8593db351
Reported here: https://bugs.ruby-lang.org/issues/9820
Fixed    here: https://github.com/ruby/ruby/commit/3771a370ad64aae87f751751e80d52d02a1735a9
Fix syntax error on Ruby 2.2.x

Fixes Issue1 from #27