Add support for cloud integration testing on ec2 and digitalocean

I've been having issues using this cookbook to install Go server on an AWS ec2 micro instance, so in an effort to figure out why I put this together. I've never made a pull request before but I don't see why this shouldn't be added to the official repository. I assume most people will be trying to install on a cloud platform anyway. 

These changes are modeled after patterns used in the official opscode cookbooks for cloud integration testing. I even borrowed the snipet used in their TESTING.md. I've also run the current serverspec tests on the two platforms I included with no errors.