Index: wp-admin/includes/upgrade.php
===================================================================
--- wp-admin/includes/upgrade.php	(revision 18787)
+++ wp-admin/includes/upgrade.php	(working copy)
@@ -451,6 +451,9 @@
 	if ( $wp_current_db_version < 15260 )
 		upgrade_300();
 
+	if ( $wp_current_db_version < 19999 )
+		upgrade_330();
+
 	maybe_disable_automattic_widgets();
 
 	update_option( 'db_version', $wp_db_version );
@@ -1132,6 +1135,19 @@
 }
 
 /**
+ * Execute changes made in WordPress 3.3.
+ *
+ * @since 3.3.0
+ */
+function upgrade_330() {
+	global $wp_current_db_version, $wpdb;
+
+	if ( is_main_site() && ! defined( 'DO_NOT_UPGRADE_GLOBAL_TABLES' ) ) {
+		$wpdb->query( "DELETE FROM $wpdb->usermeta WHERE meta_key IN ('show_admin_bar_admin', 'plugins_last_view')" );
+	}
+}
+
+/**
  * Execute network level changes
  *
  * @since 3.0.0