upgrade net-ssh from 2.6.5 to 2.9.1

~~Developers and the CentOS appliance use `net-ssh` 2.9.1.~~
We currently use use `net-ssh` 2.6.5.
There are bugs with password usage in all the versions until the current version 2.9.1.

I would like to upgrade to the latest gem version, but would like input in terms of what components we need to test and verify

So far:

- [ ] `fog`
- [ ] `shell_exec`
- [x] `appliance_console` copying encryption keys [this PR is blocking #528 ]