Don't run torquebox capistrano tasks on 'no release' servers

My deploy.rb has a database server role configured like so:

```ruby
role :db,  "...", :primary => true, :no_release => true
```

However, the torquebox capistrano tasks still try to ssh into this server and deploy to it, which causes the whole deploy process to fail.

This fix skips the torquebox tasks if :no_release is true, as expected.

I wanted to test it, but Bundler can't link to a git repo's subdirectory without a .gemspec. You might consider creating some .gemspecs to make Bundler happy.