Travis build test following serverspec v2.0

Hello, I have some issues with busser-serverspec since we release serverspec2.

```
       /opt/chef/embedded/bin/ruby -I/tmp/busser/suites/serverspec -I/tmp/busser/gems/gems/rspec-support-3.0.4/lib:/tmp/busser/gems/gems/rspec-core-3.0.4/lib -S /opt/chef/embedded/bin/rspec /tmp/busser/suites/serverspec/default_spec.rb --color --format documentation
       /tmp/busser/suites/serverspec/spec_helper.rb:4:in `<top (required)>': uninitialized constant Serverspec::Helper::Exec (NameError)
       	from /tmp/busser/suites/serverspec/default_spec.rb:3:in `require_relative'
       	from /tmp/busser/suites/serverspec/default_spec.rb:3:in `<top (required)>'
       	from /tmp/busser/gems/gems/rspec-core-3.0.4/lib/rspec/core/configuration.rb:1058:in `load'
       	from /tmp/busser/gems/gems/rspec-core-3.0.4/lib/rspec/core/configuration.rb:1058:in `block in load_spec_files'
       	from /tmp/busser/gems/gems/rspec-core-3.0.4/lib/rspec/core/configuration.rb:1058:in `each'
       	from /tmp/busser/gems/gems/rspec-core-3.0.4/lib/rspec/core/configuration.rb:1058:in `load_spec_files'
       	from /tmp/busser/gems/gems/rspec-core-3.0.4/lib/rspec/core/runner.rb:97:in `setup'
       	from /tmp/busser/gems/gems/rspec-core-3.0.4/lib/rspec/core/runner.rb:85:in `run'
       	from /tmp/busser/gems/gems/rspec-core-3.0.4/lib/rspec/core/runner.rb:70:in `run'
       	from /tmp/busser/gems/gems/rspec-core-3.0.4/lib/rspec/core/runner.rb:38:in `invoke'
       	from /tmp/busser/gems/gems/rspec-core-3.0.4/exe/rspec:4:in `<top (required)>'
       	from /opt/chef/embedded/bin/rspec:23:in `load'
       	from /opt/chef/embedded/bin/rspec:23:in `<main>'
```


this PR is a fake just to trigger travil build