Fix handling ssh-config of multi-vm files

[megamisan]

When using a Vagrantfile with multiple declared machines, saved ssh-config is wrong.

Currently, this call is done: vagrant ssh-config --host #{hostname}. The host parameter tell Vagrant how to name the entry.
With machines db and app, and respective hostnames project-db and project-app, the result for each looks like:

# VAGRANT: hash (db) / uuid
Host project-db
  HostName 127.0.0.1
  User vagrant
  Port 2222
  […]
Host project-db
  HostName 127.0.0.1
  User vagrant
  Port 2201
  […]
# VAGRANT: hash (db) / uuid
# VAGRANT: hash (app) / uuid
Host project-app
  HostName 127.0.0.1
  User vagrant
  Port 2222
  […]
Host project-app
  HostName 127.0.0.1
  User vagrant
  Port 2201
  […]
# VAGRANT: hash (app) / uuid

Which does not work well.

To fix this, it is required to add the machine name to the ssh-config call. Which results to vagrant ssh-config --host #{hostname} #{name} and a clean ssh-config file :

# VAGRANT: hash (db) / uuid
Host project-db
  HostName 127.0.0.1
  User vagrant
  Port 2222
  […]
# VAGRANT: hash (db) / uuid
# VAGRANT: hash (app) / uuid
Host project-app
  HostName 127.0.0.1
  User vagrant
  Port 2201
  […]
# VAGRANT: hash (app) / uuid