Don't use SSH in Rackspace::Cloud::Server

Rackspace Cloud Servers now supports config drive and the Rackspace
images have cloud-init installed by default, so we no longer have to SSH
to the Cloud Server to install dependencies and run the user-data
script.

Closes-Bug: #1298050
Change-Id: I5cb6a93c5b34b0a8cfe7480211da70d65638de54
Merge "Don't use SSH in Rackspace::Cloud::Server"