Rename Vagrant boxes

Matching distro/name name

Vagrantfile

@@ -6,7 +6,7 @@ Vagrant.configure(2) do |config|
     vb.memory = "512"
   end
 
-  config.vm.define "centos" do |machine|
+  config.vm.define "centos-7" do |machine|
     machine.vm.box = "minimal/centos7"
     machine.vm.provision "shell", inline: "yum update -y"
     machine.vm.provision "ansible" do |ansible|
@@ -14,7 +14,7 @@ Vagrant.configure(2) do |config|
     end
   end
 
-  config.vm.define "debian" do |machine|
+  config.vm.define "debian-jessie" do |machine|
     machine.vm.box = "minimal/jessie64"
     machine.vm.provision "shell", inline: "apt-get update && apt-get install -y python"
     machine.vm.provision "ansible" do |ansible|