title: Change ansible role_path with vagrant provision
body: <p>I have a bunch of ansible galaxy roles and a bunch of custom roles.</p>
  
  <p>The problem is that I can't load custom roles AND galaxy roles at the same time using a Vagrantfile <code>:ansible</code> provisionner.</p>
  
  <p>Without vagrant, this command works well as I added the <code>ANSIBLE_ROLES_PATH</code> environment variable: </p>
  
  <pre><code> ANSIBLE_ROLES_PATH=./custom_roles ansible-playbook project.yml --inventory dev.ini -vvvv --ask-sudo-pass
  </code></pre>
  
  <p>My Vagrant configuration is the following:</p>
  
  <pre><code>config.vm.provision :ansible do |ansible|
     ansible.raw_arguments = ['--timeout=300']
     ansible.playbook = "project.yml"
     ansible.verbose = "vvv"
     ansible.groups = {
       "env-dev:children" =&gt; ["app-web", "app-db"],
       "app-web" =&gt; ["my-app"],
       "app-db" =&gt; ["my-app"],
     }
   end
  </code></pre>
  
  <p>I can see that ansible auto-load roles inside <code>./roles</code> but I can't add my custom roles to this directory due to version control (<code>./roles</code> is in my <code>.gitignore</code>)</p>
  
  <p>Here is the directory structure to have a better view of what's going on:</p>
  
  <pre><code> - roles/
       - postgresql/...
       - php/...
   - custom_roles/
       - my-role-1/...
       - my-role-1/...
   - .gitignore         &lt;- ignore ./roles
   - project.yml
   - roles.yml
   - dev.ini
   - Vagrantfile
  </code></pre>