Make salt cloud bail on error'ed ssh commands
Fallback to `rsync` if `scp` is not available.

This happens with the Cent 5 image from Rackspace
No need to format the string
Remove unused variable
Remove unused variable
Add `allow_failure` to `root_cmd`
Try `sftp` before `rsync`
Merge pull request #15158 from s0undt3ch/hotfix/salt-cloud-upload-fixes

Make salt-cloud fail on upload failures