Can't add from internal URL

[Jeffrey Bilbro]

I have worked through building my first Vagrant and VMware images with Packer - super cool!  I'm now trying to create an internal Git repository with a Vagrantfile and am hosting the Vagrant .box file and a metadata.json on an internal public Git repo, as well.  However, I'm having a problem when I try to do a 'vagrant up' from that Vagrant file.  I get the following error:

The box you're adding has a name different from the name you

requested. For boxes with metadata, you cannot override the name.

If you're adding a box using `vagrant box add`, don't specify

the `--name` parameter. If the box is being added via a Vagrantfile,

change the `config.vm.box` value to match the name below.

Requested name: foo/centos-7

Actual name: 

How do I get past this?  

My Vagrant file has these lines in it:

  config.vm.box = "foo/centos-7"

  config.vm.box_url = "https://foo.example.com/projects/INFRA/repos/images/browse/centos7/metadata.json"

Thanks!

-Jeff