Use WP_FALLBACK_THEME when creating default stylesheet and template options.

git-svn-id: https://develop.svn.wordpress.org/trunk@13736 602fd350-edb4-49c9-b593-d223f7449a82

wp-admin/includes/schema.php

@@ -247,8 +247,8 @@ function populate_options() {
 	'default_email_category' => 1,
 	'recently_edited' => '',
 	'use_linksupdate' => 0,
-	'template' => 'twentyten',
-	'stylesheet' => 'twentyten',
+	'template' => WP_FALLBACK_THEME,
+	'stylesheet' => WP_FALLBACK_THEME,
 	'comment_whitelist' => 1,
 	'blacklist_keys' => '',
 	'comment_registration' => 0,