Document how to get geerlingguy/centos6 Vagrant box

[pdurbin]

I'm resuming work on IQSS/dataverse#3352 and thought I'd run vagrant up so I have a DCM instance to develop against. I got this error:

murphy:data-capture-module pdurbin$ vagrant up
Bringing machine 'default' up with 'virtualbox' provider...
==> default: Box 'geerlingguy/centos6' could not be found. Attempting to find and install...
    default: Box Provider: virtualbox
    default: Box Version: >= 0
The box 'geerlingguy/centos6' could not be found or
could not be accessed in the remote catalog. If this is a private
box on HashiCorp's Atlas, please verify you're logged in via
`vagrant login`. Also, please double-check the name. The expanded
URL and error message are shown below:

URL: ["https://atlas.hashicorp.com/geerlingguy/centos6"]
Error: 
murphy:data-capture-module pdurbin$

[pdurbin]

@pameyer do you care if I switch it to this one? https://github.com/IQSS/dataverse/blob/v4.5.1/Vagrantfile#L16

[pdurbin]

Uh oh, problems with that base box too: IQSS/dataverse#3460

[pameyer]

Does vagrant box add geerlingguy/centos6 (or analogous for the other box) also fail?

[pdurbin]

I'm guessing I'm running into hashicorp/vagrant#7969 since I'm running Vagrant 1.8.7 as I mentioned at IQSS/dataverse#3460

There's a suggestion at hashicorp/vagrant#7970 that there's something wrong with /opt/vagrant/embedded/bin/curl so I moved it aside and now I'm able to download the box:

murphy:data-capture-module pdurbin$ file /opt/vagrant/embedded/bin/curl
/opt/vagrant/embedded/bin/curl: Mach-O 64-bit executable x86_64
murphy:data-capture-module pdurbin$ sudo mv /opt/vagrant/embedded/bin/curl /opt/vagrant/embedded/bin/curl.moved
Password:
murphy:data-capture-module pdurbin$ vagrant up
Bringing machine 'default' up with 'virtualbox' provider...
==> default: Box 'geerlingguy/centos6' could not be found. Attempting to find and install...
    default: Box Provider: virtualbox
    default: Box Version: >= 0
==> default: Loading metadata for box 'geerlingguy/centos6'
    default: URL: https://atlas.hashicorp.com/geerlingguy/centos6
==> default: Adding box 'geerlingguy/centos6' (v1.1.3) for provider: virtualbox
    default: Downloading: https://atlas.hashicorp.com/geerlingguy/boxes/centos6/versions/1.1.3/providers/virtualbox.box
==> default: Successfully added box 'geerlingguy/centos6' (v1.1.3) for 'virtualbox'!
==> default: Importing base box 'geerlingguy/centos6'...