Removed symbolic link loop from spec/dummy app

Hi,

We found that you got infinite symbolic link loop in test app, which causes some problems with filesystem when we run test on our CI (Semaphore - https://semaphoreapp.com).

It's like:
```bash
File system loop detected; `./vendor/bundle/ruby/1.9.1/bundler/gems/obfuscate_id-a88c4764d59d/spec/dummy/spec' is part of the same file system loop as `./vendor/bundle/ruby/1.9.1/bundler/gems/obfuscate_id-a88c4764d59d/spec'.
```

This PR removes symbolic link from spec/dummy app, it's not necessary anyway,
please correct me If I'm wrong?


Cheers,
Aleksandar