increase readability of fallback in parallel

It increases readability of deployment:

```bash
  * executing multiple commands in parallel
    -> "in?(:rvm)" :: "rvm_path=$HOME/.rvm/ $HOME/.rvm/bin/rvm-shell 'ruby-1.9.3-p385@ad' -c 'ls -x /home/ad/app/releases'"
    -> "else" :: "sh -c 'ls -x /home/ad/app/releases'"
```