Dependency gems not installed automatically on EngineYard systems

I recently tried to install the engineyard-jenkins gem on a fresh EngineYard instance.

After running the initial "sudo gem install engineyard-jenkins" command, there was an error that the "rest-client" gem was required and was not installed. This was surprising, as usually gems install their own dependencies. I installed this gem and then attempted engineyard-jenkins again. Again, I hit another dependency error.

The following was the sequence of commands that I needed to run to get this to successfully install. Why were these dependencies not loaded automatically by the engineyard-jenkins gem?

```
sudo gem install rest-client
sudo gem install highline
sudo gem install json_pure
sudo gem install escape
sudo gem install engineyard-serverside-adapter --version 1.4.16
sudo gem install net-ssh --version 2.1.0
sudo gem install launchy --version 2.0.5
sudo gem install jenkins
sudo gem install engineyard-jenkins
```