smarter sudo detection

It implements `sudo` detection on the remote server so we avoid issues when a user calls ceph-deploy with `sudo` or while being the root user and ceph-deploy then assumes that `sudo` will no longer be needed which is a lie if you are connecting via a non-sudo user.

Uses the following fix in remoto https://github.com/alfredodeza/remoto/issues/7

`remoto` commit was: https://github.com/alfredodeza/remoto/commit/63f0ba770dbe79ae7838ce8491c4b639c4d8c941

Reference issue: http://tracker.ceph.com/issues/9565