Fix vagrant deployment for vagrant version > 1.7

See: https://github.com/mitchellh/vagrant/issues/5048.

Closes: #172

Signed-off-by: Sébastien Han <sebastien.han@enovance.com>

Vagrantfile

@@ -39,6 +39,7 @@ end
 
 Vagrant.configure(VAGRANTFILE_API_VERSION) do |config|
   config.vm.box = 'hashicorp/precise64'
+  config.ssh.insert_key = false # workaround for https://github.com/mitchellh/vagrant/issues/5048
 
   (0..CLIENTS - 1).each do |i|
     config.vm.define "client#{i}" do |client|