Clear all transients (regardless of expiration) on all database upgrades. see #20316.

git-svn-id: https://develop.svn.wordpress.org/trunk@25416 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-admin/includes/schema.php

@@ -546,6 +546,8 @@ function populate_options() {
 
 	// delete obsolete magpie stuff
 	$wpdb->query("DELETE FROM $wpdb->options WHERE option_name REGEXP '^rss_[0-9a-f]{32}(_ts)?$'");
+	// clear transient data
+	$wpdb->query( "DELETE FROM $wpdb->options WHERE option_name LIKE '\_transient\_%' OR option_name LIKE '\_site\_transient\_%'" );
 }
 
 /**