Hi,

I wanted to try vagrant box of Centos7 for my vm but I encounter problems during setting up a vm.

I did very basic setup, in empty folder I did

```

vagrant init centos/7

vagrant up

```

In a result it repetitively promts

```

default: Warning: Authentication failure. Retrying...

```

Full output here: http://pastebin.com/JrQHER6L

I am using Linux Mint 17.3 with VirtualBox 5 and Vagrant 1.8.5.