Set virtualbox network to virtio for speed

vagrant/base/devstack/Vagrantfile

@@ -35,7 +35,7 @@ Vagrant.configure(VAGRANTFILE_API_VERSION) do |config|
   config.vm.box     = "precise64"
   config.vm.box_url = "http://files.vagrantup.com/precise64.box"
 
-  config.vm.network :private_network, ip: vm_guest_ip
+  config.vm.network :private_network, ip: vm_guest_ip, nic_type: "virtio"
 
   # If you want to run the box but don't need network ports, set VAGRANT_NO_PORTS=1.
   # This is useful if you want to run more than one box at once.

vagrant/release/devstack/Vagrantfile

@@ -109,7 +109,7 @@ Vagrant.configure(VAGRANTFILE_API_VERSION) do |config|
   config.vm.box     = boxname
   config.vm.box_url = "http://files.edx.org/vagrant-images/#{boxfile}"
 
-  config.vm.network :private_network, ip: "192.168.33.10"
+  config.vm.network :private_network, ip: "192.168.33.10", nic_type: "virtio"
 
   # If you want to run the box but don't need network ports, set VAGRANT_NO_PORTS=1.
   # This is useful if you want to run more than one box at once.