potential fix for #438, telling DO to get user "vagrant" created on provision

Author: fideloper

Vagrantfile

@@ -158,6 +158,7 @@ Vagrant.configure("2") do |config|
   # Needs to ensure that the vagrant plugin is installed
   config.vm.provider :digital_ocean do |provider, override|
     override.ssh.private_key_path = '~/.ssh/id_rsa'
+    override.ssh.username = 'vagrant'
     override.vm.box = 'digital_ocean'
     override.vm.box_url = "https://github.com/smdahlen/vagrant-digitalocean/raw/master/box/digital_ocean.box"