email selfregistration enabled by default again - thanks Eloy for noticing the problem; backported from HEAD

admin/index.php

@@ -207,6 +207,7 @@
                                                    'enrol' => 'manual',
                                                    'enrol_plugins_enabled' => 'manual',
                                                    'guestloginbutton' => 1,
+                                                   'registerauth' => 'email',
                                                    'style' => 'default',
                                                    'template' => 'default',
                                                    'theme' => 'standardwhite',

lib/db/upgrade.php

@@ -133,6 +133,11 @@ function xmldb_main_upgrade($oldversion=0) {
 
     // Move the auth plugin settings into the config_plugin table
     if ($oldversion < 2007010300) {
+        if ($CFG->auth == 'email') {
+            set_config('registerauth', 'email');
+        } else {
+            set_config('registerauth', '');
+        }
         $authplugins = get_list_of_plugins('auth');
         foreach ($CFG as $k => $v) {
             if (strpos($k, 'auth_') !== 0) {