Now there's a 'ldap' USE flag in the puppet ebuild, but it didn't install the puppet.schema file yet into the right place. The patch which will be attached to this bugreport adds this functionality to the current app-admin/puppet-0.24.5-r3 ebuild.
Created attachment 167087 [details, diff] Patch for app-admin/puppet-0.24.5-r3 to install puppet.schema into /etc/openldap/schema
0.24.5-r4 in cvs