Update templates/default/hosts.cfg.erb

Fix template syntax so that cookbook can be uploaded to Chef server. Was experiencing the following error:

```
FATAL: Erb template templates/default/hosts.cfg.erb has a syntax error:
FATAL: -:25: syntax error, unexpected keyword_elsif, expecting keyword_end
FATAL:   elsif !node['cloud'].nil? && n['cl...
FATAL:        ^
FATAL: -:27: syntax error, unexpected keyword_else, expecting keyword_end
```