Reusing getAvailableConnections() to avoid conflicts

Even though I tested several times that my previous pull request was working as expected, I just started having issues again - I suspect that my cache hadn't been properly cleaned when I performed tests for the previous pull request.

This change "caches" `getAvailableConnections()`, this is necessary because:

* The first call to `getAvailableConnections()` fetches connections from the remote config
* Subsequent calls uses Rocketeers own list of available connections
* The end of `storeServerCredentials()` creates this list and thus overrides the remote config.

This prevented the next items in the list from using already stored credentials, thus resulting in Rocketeer asking for hostname, etc.

I hope that this is the end of that issue :)