RubyScript: added termination of ScriptingContainer.

Lite clearing exchanged by full termination. Reason is opened files when Cucumber was using.
```ruby
    out_html = 'cucumber_result.html'
    args = [
      '--format', 'pretty',
      '--format', 'html',
      '--out', out_html
    ]
    require 'cucumber/rspec/disable_option_parser'
    require 'cucumber/cli/main'
    Cucumber::Cli::Main.new(args).execute!

    # out_html is not closed yet....
```