Host always shows as "mech" when running "mech ssh-config" command

When you run the `mech ssh-config` command, it always shows the host as `mech`.

For instance:

```
$ mech ssh-config centos8
Host mech
  User vagrant
  Port 22
  UserKnownHostsFile /dev/null
  StrictHostKeyChecking no
  PasswordAuthentication no
  IdentityFile /Users/mikekinney/.mech/insecure_private_key
  IdentitiesOnly yes
  LogLevel FATAL
  HostName 192.168.2.219
```