fixing vagrantfile

Change-Id: I1725d15903159181a808bfc0676f93decbc37b32
diff --git a/Vagrantfile b/Vagrantfile
index ca681d2..b4433ae 100644
--- a/Vagrantfile
+++ b/Vagrantfile
@@ -51,7 +51,7 @@
   end
 
   config.vm.define "testbox" do |d|
-    config.vm.box = "fgrehm/trusty64-lxc"
+    d.vm.box = "fgrehm/trusty64-lxc"
     d.ssh.forward_agent = true
     d.vm.hostname = "testbox"
     d.vm.network "private_network", ip: "10.0.3.100", lxc__bridge_name: 'lxcbr0'