forgot to use ldap_principal_name_override when defined

manifests/ldap.pp

@@ -19,6 +19,8 @@ class shibb_idp3::ldap (
       'dev':   { $ldap_principal_name = 'service/shibboleth-dev' }
       default: { fail("unknown environment ${shibb_idp3::env}") }
     }
+  } else {
+    $ldap_principal_name = $ldap_principal_name_override
   }
 
   # Get the keytab wallet object.