Prepare Drupal 7.21 release.

CHANGELOG.txt

 
+Drupal 7.21, 2013-03-06
+-----------------------
+- Allowed sites using the 'image_allow_insecure_derivatives' variable to still
+  have partial protection from the security issues fixed in Drupal 7.20.
+
 Drupal 7.20, 2013-02-20
 -----------------------
 - Fixed security issues (denial of service). See SA-CORE-2013-002.

includes/bootstrap.inc

@@ -8,7 +8,7 @@
 /**
  * The current system version.
  */
-define('VERSION', '7.20');
+define('VERSION', '7.21');
 
 /**
  * Core API compatibility.