Fix ldap for dev vm.

The ldap config for the dev vm was not working.  This is a quick fix
until a deeper dive can be arranged.

Several errors were encountered, depending on whatever permute of config
settings were tried.  Here are a few:

$ vagrant status
Current machine states:

ldap                      not created (virtualbox)
chef-server               running (virtualbox)

==> ldap: Running provisioner: chef_zero...
    ldap: Installing Chef (latest)...
Vagrant could not detect Chef on the guest! Even after Vagrant
attempted to install Chef, it could still not find Chef on the system.
Please make sure you are connected to the Internet and can access
Chef's package distribution servers. If you already have Chef
installed on this guest, you can disable the automatic Chef detection
by setting the 'install' option in the Chef configuration section of
your Vagrantfile:

    chef.install = false

Signed-off-by: Lincoln Baker <lbaker@chef.io>

dev/Vagrantfile

@@ -245,6 +245,7 @@ def define_ldap_server(config, attributes)
     chef.cookbooks_path = "cookbooks"
     chef.add_recipe("provisioning::ldap-server")
     chef.nodes_path = "nodes"
+    chef.install = false
     chef.json = {
       'provisioning' => { 'hosts' =>  ips_to_fqdns },
       'ldap' => {'password' => LDAP_PASSWORD }